PythonForBeginners-中文系列教程-三-

IndexError:list index out of range

myList = [1, 2, 23, 32, 12, 44, 34, 55, 46, 21, 12]
print("The list is:", myList)
list_len = len(myList)
print("Length of the list is:", list_len)

The list is: [1, 2, 23, 32, 12, 44, 34, 55, 46, 21, 12]
Length of the list is: 11

sequence = range(11)
print("The sequence is:", sequence)

The sequence is: range(0, 11)

myList = [11, 2, 23, 1, 32, 12, 44, 34, 55, 46, 21, 1, 12]
print("The list is:", myList)
min_index = 0
list_len = len(myList)
for index in range(list_len):
    if myList[index] < myList[min_index]:
        min_index = index
print("Index of the minimum element is:", min_index)

The list is: [11, 2, 23, 1, 32, 12, 44, 34, 55, 46, 21, 1, 12]
Index of the minimum element is: 3

myList = [11, 2, 23, 1, 32, 12, 44, 34, 55, 46, 21, 1, 12]
print("The list is:", myList)
min_index = 0
list_len = len(myList)
for index in range(list_len):
    if myList[index] <= myList[min_index]:
        min_index = index
print("Index of the minimum element is:", min_index)

The list is: [11, 2, 23, 1, 32, 12, 44, 34, 55, 46, 21, 1, 12]
Index of the minimum element is: 11

myList = [11, 2, 23, 1, 32, 12, 44, 34, 55, 46, 21, 1, 12]
print("The list is:", myList)
min_val = min(myList)
print("The minimum value is:", min_val)

The list is: [11, 2, 23, 1, 32, 12, 44, 34, 55, 46, 21, 1, 12]
The minimum value is: 1

myList = [11, 2, 23, 1, 32, 12, 44, 34, 55, 46, 21, 1, 12]
print("The list is:", myList)
index = myList.index(23)
print("Index of 23 is:", index)

The list is: [11, 2, 23, 1, 32, 12, 44, 34, 55, 46, 21, 1, 12]
Index of 23 is: 2

myList = [11, 2, 23, 1, 32, 12, 44, 34, 55, 46, 21, 1, 12]
print("The list is:", myList)
index = myList.index(105)
print("Index of 105 is:", index)

The list is: [11, 2, 23, 1, 32, 12, 44, 34, 55, 46, 21, 1, 12]
Traceback (most recent call last):
  File "/home/aditya1117/PycharmProjects/pythonProject/string12.py", line 3, in <module>
    index = myList.index(105)
ValueError: 105 is not in list

myList = [11, 2, 23, 1, 32, 12, 44, 34, 55, 46, 21, 1, 12]
print("The list is:", myList)
min_val = min(myList)
index = myList.index(min_val)
print("Index of minimum value is:", index)

The list is: [11, 2, 23, 1, 32, 12, 44, 34, 55, 46, 21, 1, 12]
Index of minimum value is: 3

import numpy

myList = [11, 2, 23, 1, 32, 12, 44, 34, 55, 46, 21, 1, 12]
print("The list is:", myList)
array = numpy.array(myList)
print("The array is:", array)

The list is: [11, 2, 23, 1, 32, 12, 44, 34, 55, 46, 21, 1, 12]
The array is: [11  2 23  1 32 12 44 34 55 46 21  1 12]

import numpy

myList = [11, 2, 23, 1, 32, 12, 44, 34, 55, 46, 21, 1, 12]
print("The list is:", myList)
array = numpy.array(myList)
min_index = array.argmin()
print("Index of minimum element is:", min_index)

The list is: [11, 2, 23, 1, 32, 12, 44, 34, 55, 46, 21, 1, 12]
Index of minimum element is: 3

myList = [11, 2, 23, 1, 32, 12, 44, 34, 55, 46, 21, 1, 12]
print("The list is:", myList)
min_val = min(myList)
list_indices = []
list_len = len(myList)
sequence = range(list_len)
for index in sequence:
    if myList[index] == min_val:
        list_indices.append(index)
print("Indices of minimum element are:", list_indices)

The list is: [11, 2, 23, 1, 32, 12, 44, 34, 55, 46, 21, 1, 12]
Indices of minimum element are: [3, 11]

new_list=[f(element) for element in existing_list if condition]

myList = [11, 2, 23, 1, 32, 12, 44, 34, 55, 46, 21, 1, 12]
print("The list is:", myList)
min_val = min(myList)
list_len = len(myList)
sequence = range(list_len)
new_list = [index for index in sequence if myList[index] == min_val]
print("Indices of minimum element are:", new_list)

The list is: [11, 2, 23, 1, 32, 12, 44, 34, 55, 46, 21, 1, 12]
Indices of minimum element are: [3, 11]

myList = [11, 2, 23, 1, 32, 12, 44, 34, 55, 46, 21, 1, 12]
print("The list is:", myList)
enumerated_list = list(enumerate(myList))
print("Enumerated list is:", enumerated_list)

The list is: [11, 2, 23, 1, 32, 12, 44, 34, 55, 46, 21, 1, 12]
Enumerated list is: [(0, 11), (1, 2), (2, 23), (3, 1), (4, 32), (5, 12), (6, 44), (7, 34), (8, 55), (9, 46), (10, 21), (11, 1), (12, 12)]

myList = [11, 2, 23, 1, 32, 12, 44, 34, 55, 46, 21, 1, 12]
print("The list is:", myList)
enumerated_list = list(enumerate(myList))
min_indices = []
min_element = min(myList)
for element_tuple in enumerated_list:
    index = element_tuple[0]
    element = element_tuple[1]
    if element == min_element:
        min_indices.append(index)
print("Indices of minimum element are:", min_indices)

The list is: [11, 2, 23, 1, 32, 12, 44, 34, 55, 46, 21, 1, 12]
Indices of minimum element are: [3, 11]

myList = [11, 2, 23, 1, 32, 12, 44, 34, 55, 46, 21, 1, 12]
print("The list is:", myList)
enumerated_list = list(enumerate(myList))
min_element = min(myList)
min_indices = [index for (index, element) in enumerated_list if element == min_element]
print("Indices of minimum element are:", min_indices)

The list is: [11, 2, 23, 1, 32, 12, 44, 34, 55, 46, 21, 1, 12]
Indices of minimum element are: [3, 11]

myList = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
print("The list is:", myList)
index = 10
element = myList[index]
print("Element at index {} is {}".format(index,element))

The list is: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
Traceback (most recent call last):
  File "/home/aditya1117/PycharmProjects/pythonProject/string12.py", line 4, in <module>
    element = myList[index]
IndexError: list index out of range

myTuple = (1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
print("The Tuple is:", myTuple)
index = 10
element = myTuple[index]
print("Element at index {} is {}".format(index,element))

The Tuple is: (1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
Traceback (most recent call last):
  File "/home/aditya1117/PycharmProjects/pythonProject/string12.py", line 4, in <module>
    element = myTuple[index]
IndexError: tuple index out of range

myTuple = (1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
print("The Tuple is:", myTuple)
index = 10
print("Index is:",index)
if index <= 9:
    element = myTuple[index]
    print("Element at index {} is {}".format(index, element))
else:
    print("Index should be smaller.")

The Tuple is: (1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
Index is: 10
Index should be smaller.

myTuple = (1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
print("The Tuple is:", myTuple)
index = 10
print("Index is:",index)
try:
    element = myTuple[index]
    print("Element at index {} is {}".format(index, element))
except IndexError:
    print("Index should be smaller.")

The Tuple is: (1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
Index is: 10
Index should be smaller.

import pandas as pd
import numpy as np
names=pd.read_csv("name.csv")
grades=pd.read_csv("grade.csv")
resultdf=names.merge(grades,how="inner",on="Name")
print("The resultant dataframe is:")
print(resultdf)

The resultant dataframe is:
   Class_x  Roll_x    Name  Class_y  Roll_y Grade
0        1      11  Aditya        1      11     A
1        1      12   Chris        1      12    A+
2        2       1    Joel        2       1     B
3        2      22     Tom        2      22    B+
4        3      33    Tina        3      33    A-
5        3      34     Amy        3      34     A

import pandas as pd
import numpy as np
names=pd.read_csv("name.csv")
grades=pd.read_csv("grade.csv")
grades=grades.set_index("Name")
resultdf=names.join(grades,how="inner",on="Name",lsuffix='_names', rsuffix='_grades')
print("The resultant dataframe is:")
print(resultdf)

The resultant dataframe is:
   Class_names  Roll_names    Name  Class_grades  Roll_grades Grade
0            1          11  Aditya             1           11     A
1            1          12   Chris             1           12    A+
3            2           1    Joel             2            1     B
4            2          22     Tom             2           22    B+
6            3          33    Tina             3           33    A-
7            3          34     Amy             3           34     A

myList = [1, 2, 3, 5, 6, 7, 8, 9, 10]
print("Original list is:", myList)
element = 4
print("The element to be inserted is:", element)
l = len(myList)
index = 0
for i in range(l):
    if myList[i] > element:
        index = i
        break
myList = myList[:index] + [element] + myList[index:]
print("The updated list is:", myList)

Original list is: [1, 2, 3, 5, 6, 7, 8, 9, 10]
The element to be inserted is: 4
The updated list is: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

myList = [1, 2, 3, 5, 6, 7, 8, 9, 10]
print("Original list is:", myList)
element = 4
print("The element to be inserted is:", element)
l = len(myList)
index = 0
for i in range(l):
    if myList[i] > element:
        index = i
        break
myList.insert(index, element)
print("The updated list is:", myList)

Original list is: [1, 2, 3, 5, 6, 7, 8, 9, 10]
The element to be inserted is: 4
The updated list is: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

import bisect

myList = [1, 2, 3, 5, 6, 7, 8, 9, 10]
print("Original list is:", myList)
element = 4
print("The element to be inserted is:", element)
bisect.insort(myList, element)
print("The updated list is:", myList)

Original list is: [1, 2, 3, 5, 6, 7, 8, 9, 10]
The element to be inserted is: 4
The updated list is: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

import pandas as pd

df = pd.read_csv('Demo.csv')
print("The dataframe before inserting the column:")
print(df)
column_data = [180, 164, 170]
df['Height'] = column_data
print("The dataframe after inserting the column:")
print(df) 

The dataframe before inserting the column:
   Roll    Name Language
0     1  Aditya   Python
1     2     Sam     Java
2     3   Chris      C++
The dataframe after inserting the column:
   Roll    Name Language  Height
0     1  Aditya   Python     180
1     2     Sam     Java     164
2     3   Chris      C++     170

import pandas as pd

df = pd.read_csv('Demo.csv')
print("The dataframe before inserting the column:")
print(df)
column_data = [180, 164, 170]
df = df.assign(Height=column_data)
print("The dataframe after inserting the column:")
print(df)

The dataframe before inserting the column:
   Roll    Name Language
0     1  Aditya   Python
1     2     Sam     Java
2     3   Chris      C++
The dataframe after inserting the column:
   Roll    Name Language  Height
0     1  Aditya   Python     180
1     2     Sam     Java     164
2     3   Chris      C++     170 

import pandas as pd

df = pd.read_csv('Demo.csv')
print("The dataframe before inserting the column:")
print(df)
column_data = [180, 164, 170]
df.insert(1, 'Height', column_data)
print("The dataframe after inserting the column:")
print(df)

The dataframe before inserting the column:
   Roll    Name Language
0     1  Aditya   Python
1     2     Sam     Java
2     3   Chris      C++
The dataframe after inserting the column:
   Roll  Height    Name Language
0     1     180  Aditya   Python
1     2     164     Sam     Java
2     3     170   Chris      C++

list1 = [1, 2, 3, 4, 5, 6]
print("First list is:", list1)
list2 = [2, 4, 6, 8, 10, 12]
print("Second list is:", list2)
newList = []
for element in list1:
    if element in list2:
        newList.append(element)
print("Intersection of the lists is:", newList)

First list is: [1, 2, 3, 4, 5, 6]
Second list is: [2, 4, 6, 8, 10, 12]
Intersection of the lists is: [2, 4, 6]

list1 = [1, 2, 3, 4, 5, 6]
print("First list is:", list1)
list2 = [2, 4, 6, 8, 10, 12]
print("Second list is:", list2)
newList = []
for element in list2:
    if element in list1:
        newList.append(element)
print("Intersection of the lists is:", newList)

First list is: [1, 2, 3, 4, 5, 6]
Second list is: [2, 4, 6, 8, 10, 12]
Intersection of the lists is: [2, 4, 6]

list1 = [1, 2, 3, 4, 5, 6]
print("First list is:", list1)
list2 = [2, 4, 6, 8, 10, 12]
print("Second list is:", list2)
set1 = set(list1)
set2 = set(list2)
newList = list(set1.intersection(set2))
print("Intersection of the lists is:", newList)

First list is: [1, 2, 3, 4, 5, 6]
Second list is: [2, 4, 6, 8, 10, 12]
Intersection of the lists is: [2, 4, 6]

import cmath
myNum=3+2j
print("The complex number is:",myNum)
myPhase= cmath.phase(myNum)
print("Phase of  the complex number is:",myPhase)

The complex number is: (3+2j)
Phase of  the complex number is: 0.5880026035475675

import cmath
myNum=3+2j
print("The complex number is:",myNum)
myPol= cmath.polar(myNum)
print("Polar coordinates of  the complex number are:",myPol)

The complex number is: (3+2j)
Polar coordinates of  the complex number are: (3.605551275463989, 0.5880026035475675)

import cmath
myPol= (3.605551275463989, 0.5880026035475675)
print("Polar coordinates of  the complex number are:",myPol)
print("Modulus of the complex number is:",myPol[0])
print("Phase of the complex number is:",myPol[1])
myRec=cmath.rect(myPol[0],myPol[1])
print("Complex number in rectangular form is:",myRec)

Polar coordinates of  the complex number are: (3.605551275463989, 0.5880026035475675)
Modulus of the complex number is: 3.605551275463989
Phase of the complex number is: 0.5880026035475675
Complex number in rectangular form is: (3+1.9999999999999996j)

import cmath
print("Given below are some of the constants defined in cmath module.")
print("e:",cmath.e)
print("Infinity (real axis):",cmath.inf)
print("Infinity (Imaginary axis):",cmath.infj)
print("NaN (real):",cmath.nan)
print("NaN (imaginary):",cmath.nanj)
print("Pi:",cmath.pi)
print("Tau:",cmath.tau)

Given below are some of the constants defined in cmath module.
e: 2.718281828459045
Infinity (real axis): inf
Infinity (Imaginary axis): infj
NaN (real): nan
NaN (imaginary): nanj
Pi: 3.141592653589793
Tau: 6.283185307179586

import cmath
myNum=3+2j
print("Complex number is:",myNum)
print("Sine of the complex number is:",cmath.sin(myNum))
print("Cosine of the complex number is:",cmath.cos(myNum))
print("Tangent of the complex number is:",cmath.tan(myNum))
print("Inverse Sine of the complex number is:",cmath.asin(myNum))
print("Inverse Cosine of the complex number is:",cmath.acos(myNum))
print("Inverse Tangent of the complex number is:",cmath.atan(myNum)) 

Complex number is: (3+2j)
Sine of the complex number is: (0.5309210862485197-3.59056458998578j)
Cosine of the complex number is: (-3.7245455049153224-0.5118225699873846j)
Tangent of the complex number is: (-0.009884375038322495+0.965385879022133j)
Inverse Sine of the complex number is: (0.9646585044076028+1.9686379257930964j)
Inverse Cosine of the complex number is: (0.6061378223872937-1.9686379257930964j)
Inverse Tangent of the complex number is: (1.3389725222944935+0.14694666622552977j)

import cmath
myNum=3+2j
print("Complex number is:",myNum)
print("Hyperbolic Sine of the complex number is:",cmath.sinh(myNum))
print("Hyperbolic Cosine of the complex number is:",cmath.cosh(myNum))
print("Hyperbolic Tangent of the complex number is:",cmath.tanh(myNum))
print("Inverse Hyperbolic Sine of the complex number is:",cmath.asinh(myNum))
print("Inverse Hyperbolic Cosine of the complex number is:",cmath.acosh(myNum))
print("Inverse Hyperbolic Tangent of the complex number is:",cmath.atanh(myNum)) 

Complex number is: (3+2j)
Hyperbolic Sine of the complex number is: (-4.168906959966565+9.15449914691143j)
Hyperbolic Cosine of the complex number is: (-4.189625690968807+9.109227893755337j)
Hyperbolic Tangent of the complex number is: (1.00323862735361-0.003764025641504249j)
Inverse Hyperbolic Sine of the complex number is: (1.9833870299165355+0.5706527843210994j)
Inverse Hyperbolic Cosine of the complex number is: (1.9686379257930964+0.6061378223872937j)
Inverse Hyperbolic Tangent of the complex number is: (0.22907268296853878+1.4099210495965755j)

import cmath
myNum=3+2j
print("Complex number is:",myNum)
print("Natural log of the complex number is:",cmath.log(myNum))
print("Logarithm of the complex number with base 5 is:",cmath.log(myNum,5))

Complex number is: (3+2j)
Natural log of the complex number is: (1.2824746787307684+0.5880026035475675j)
Logarithm of the complex number with base 5 is: (0.7968463205835412+0.36534655919610926j)

import cmath
myNum=3+2j
print("Complex number is:",myNum)
print("Logarithm of the complex number with base 10 is:",cmath.log10(myNum))

Complex number is: (3+2j)
Logarithm of the complex number with base 10 is: (0.5569716761534184+0.255366286065454j)

import cmath
myNum=3+2j
print("Complex number is:",myNum)
print("Exponential of the complex number is:",cmath.exp(myNum)) 

Complex number is: (3+2j)
Exponential of the complex number is: (-8.358532650935372+18.263727040666765j)

 import cmath
myNum=3+2j
print("Complex number is:",myNum)
print("Square root of the complex number is:",cmath.sqrt(myNum)) 

Complex number is: (3+2j)
Square root of the complex number is: (1.8173540210239707+0.5502505227003375j)

from collections import deque

from collections import deque
myDeque= deque([1,2,3,4,5])
print("The created deque is:")
print(myDeque)

The created deque is:
deque([1, 2, 3, 4, 5])

print("Deque before insertion:")
print(myDeque)
myDeque.appendleft(0)
print("Deque after insertion of element 0 at start:")
print(myDeque)

Deque before insertion:
deque([1, 2, 3, 4, 5])
Deque after insertion of element 0 at start:
deque([0, 1, 2, 3, 4, 5])

print("Deque before insertion:")
print(myDeque)
myDeque.append(6)
print("Deque after insertion of element 6 at end:")
print(myDeque)

Deque before insertion:
deque([0, 1, 2, 3, 4, 5])
Deque after insertion of element 6 at end:
deque([0, 1, 2, 3, 4, 5, 6])

print("Deque before insertion:")
print(myDeque)
myDeque.extendleft([-2,-3,-4])
print("Deque after insertion of multiple elements at start:")
print(myDeque)

Deque before insertion:
deque([0, 1, -1, 2, 3, 4, 5, 6])
Deque after insertion of multiple elements at start:
deque([-4, -3, -2, 0, 1, -1, 2, 3, 4, 5, 6])

print("Deque before insertion:")
print(myDeque)
myDeque.extend([-5,-6,-7])
print("Deque after insertion of multiple elements at end:")
print(myDeque)

Deque before insertion:
deque([-4, -3, -2, 0, 1, -1, 2, 3, 4, 5, 6])
Deque after insertion of multiple elements at end:
deque([-4, -3, -2, 0, 1, -1, 2, 3, 4, 5, 6, -5, -6, -7])

print("Deque before insertion:")
print(myDeque)
myDeque.insert(2,-1)
print("Deque after insertion of element -1 at index 2:")
print(myDeque)

Deque before insertion:
deque([0, 1, 2, 3, 4, 5, 6])
Deque after insertion of element -1 at index 2:
deque([0, 1, -1, 2, 3, 4, 5, 6])

print("Deque before deletion of leftmost element:")
print(myDeque)
try:
    myDeque.popleft()
except IndexError:
    print("Deque is empty")
print("Deque after deletion of leftmost element:")
print(myDeque)

Deque before deletion of leftmost element:
deque([-3, -2, 0, 1, -1, 2, 3, 4, 5, 6, -5, -6, -7])
Deque after deletion of leftmost element:
deque([-2, 0, 1, -1, 2, 3, 4, 5, 6, -5, -6, -7])

print("Deque before deletion of rightmost element:")
print(myDeque)
try:
    myDeque.pop()
except IndexError:
    print("Deque is empty")
print("Deque after deletion of rightmost element:")
print(myDeque)

Deque before deletion of rightmost element:
deque([-2, 0, 1, -1, 2, 3, 4, 5, 6, -5, -6, -7])
Deque after deletion of rightmost element:
deque([-2, 0, 1, -1, 2, 3, 4, 5, 6, -5, -6])

print("Deque before deletion of element -1:")
print(myDeque)
try:
    myDeque.remove(-1)
except ValueError:
    print("Value is not present in deque")
print("Deque after deletion of element -1:")
print(myDeque)

Deque before deletion of element -1:
deque([-2, 0, 1, -1, 2, 3, 4, 5, 6, -5, -6])
Deque after deletion of element -1:
deque([-2, 0, 1, 2, 3, 4, 5, 6, -5, -6])

print("Deque is:")
print(myDeque)
n=myDeque.count(2)
print("Number of occurrences element 2 in deque is:")
print(n)

Deque is:
deque([-2, 0, 1, 2, 3, 4, 5, 6, -5, -6])
Number of occurrences element 2 in deque is:
1

print("Deque is:")
print(myDeque)
myDeque.reverse()
print("Reversed deque is:")
print(myDeque)

Deque is:
deque([-2, 0, 1, 2, 3, 4, 5, 6, -5, -6])
Reversed deque is:
deque([-6, -5, 6, 5, 4, 3, 2, 1, 0, -2])

print("Deque is:")
print(myDeque)
try:
    n=myDeque.index(4,0,9)
    print("Element 4 is at index")
    print(n)
except ValueError:
    print("Value is not present in deque")

Deque is:
deque([-6, -5, 6, 5, 4, 3, 2, 1, 0, -2])
Element 4 is at index
4

print("Deque is:")
print(myDeque)
myDeque.rotate(3)
print("deque after rotationg three steps rightwards is:")
print(myDeque)

Deque is:
deque([-6, -5, 6, 5, 4, 3, 2, 1, 0, -2])
deque after rotationg three steps rightwards is:
deque([1, 0, -2, -6, -5, 6, 5, 4, 3, 2])

# To see if I've ipython installed, I simply type "ipython" in my terminal. 

$ ipython
-bash: ipython: command not found 

$ sudo easy_install ipython
Password:
Searching for ipython
Reading http://pypi.python.org/simple/ipython/
Reading http://ipython.scipy.org
Reading http://ipython.scipy.org/dist
Reading http://ipython.org
Reading https://github.com/ipython/ipython/downloads
Reading http://ipython.scipy.org/dist/0.8.4
Reading http://ipython.scipy.org/dist/0.9.1
Reading http://archive.ipython.org/release/0.12.1
Reading http://ipython.scipy.org/dist/old/0.9
Reading http://ipython.scipy.org/dist/0.10
Reading http://archive.ipython.org/release/0.11/
Reading http://archive.ipython.org/release/0.12
Best match: ipython 0.13.1
Downloading http://pypi.python.org/packages/2.7/i/ipython/ipython-0.13.1-py2.7.egg#md5..
Processing ipython-0.13.1-py2.7.egg
creating /Library/Python/2.7/site-packages/ipython-0.13.1-py2.7.egg
Extracting ipython-0.13.1-py2.7.egg to /Library/Python/2.7/site-packages
Adding ipython 0.13.1 to easy-install.pth file
Installing ipcontroller script to /usr/local/bin
Installing iptest script to /usr/local/bin
Installing ipcluster script to /usr/local/bin
Installing ipython script to /usr/local/bin
Installing pycolor script to /usr/local/bin
Installing iplogger script to /usr/local/bin
Installing irunner script to /usr/local/bin
Installing ipengine script to /usr/local/bin
Installed /Library/Python/2.7/site-packages/ipython-0.13.1-py2.7.egg
Processing dependencies for ipython
Finished processing dependencies for ipython 

$ ipython
/Library/Python/2.7/site-packages/ipython-0.13.1-py2.7.egg/IPython/utils/rlineimpl.py:111: 
RuntimeWarning:
libedit detected - readline will not be well behaved, including but not limited to:
   * crashes on tab completion
   * incorrect history navigation
   * corrupting long-lines
   * failure to wrap or indent lines properly
It is highly recommended that you install readline, which is easy_installable:
     easy_install readline
Note that `pip install readline` generally DOES NOT WORK, because
it installs to site-packages, which come *after* lib-dynload in sys.path,
where readline is located.  It must be `easy_install readline`, or to a custom
location on your PYTHONPATH (even --user comes after lib-dyload). 

$sudo easy_install readline 

Searching for readline
Reading http://pypi.python.org/simple/readline/
Reading http://github.com/ludwigschwardt/python-readline
Reading http://www.python.org/
Best match: readline 6.2.4.1
Downloading http://pypi.python.org/packages/2.7/r/readline/readline-6.2.4.1-py2.7-macosx..
Processing readline-6.2.4.1-py2.7-macosx-10.7-intel.egg
creating /Library/Python/2.7/site-packages/readline-6.2.4.1-py2.7-macosx-10.7-intel.egg
Extracting readline-6.2.4.1-py2.7-macosx-10.7-intel.egg to /Library/Python/2.7/site-packages
Adding readline 6.2.4.1 to easy-install.pth file

Installed /Library/Python/2.7/site-packages/readline-6.2.4.1-py2.7-macosx-10.7-intel.egg
Processing dependencies for readline
Finished processing dependencies for readline 

$ ipython
Python 2.7.2 (default, Jun 20 2012, 16:23:33)
Type "copyright", "credits" or "license" for more information.

IPython 0.13.1 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object', use 'object??' for extra details.

In [1]: 

$ ipython
Python 2.7.2 (default, Jun 20 2012, 16:23:33) 
Type "copyright", "credits" or "license" for more information.

IPython 0.13.1 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object', use 'object??' for extra details. 

In [1]: from sys import std
stderr  stdin   stdout

In [1]: from urllib2 import url
url2pathname  urlopen       urlparse 

$ vim calc.py

# This is a small python script calculating numbers

a = 1 + 1

b = 2 * 2

c = 10 / 2

d = 10 - 5

print a,b,c,d 

$ ipython 
Python 2.7.2 (default, Jun 20 2012, 16:23:33) 
Type "copyright", "credits" or "license" for more information.

IPython 0.13.1 -- An enhanced Interactive Python.
?         -> Introduction and overview of IPython's features.
%quickref -> Quick reference.
help      -> Python's own help system.
object?   -> Details about 'object', use 'object??' for extra details.
3

>>> 2 4 5 5

In [1]: %run calc.py
2 4 5 5 

#In [57]: lsmagic

Available line magics:
%alias  %alias_magic  %autocall  %autoindent  %automagic  %bookmark  %cd  %colors  %config
%cpaste  %debug  %dhist  %dirs  %doctest_mode  %ed  %edit  %env  %gui  %hist  %history
%install_default_config  %install_ext  %install_profiles  %killbgscripts  %load  %load_ext
%loadpy  %logoff  %logon  %logstart  %logstate  %logstop  %lsmagic  %macro  %magic
%notebook  %page  %paste  %pastebin  %pdb  %pdef  %pdoc  %pfile  %pinfo  %pinfo2  %popd
%pprint  %precision %profile  %prun  %psearch  %psource  %pushd  %pwd  %pycat  %pylab
%quickref  %recall  %rehashx %reload_ext  %rep  %rerun  %reset  %reset_selective  %run
%save  %sc  %store  %sx  %system  %tb %time  %timeit  %unalias  %unload_ext  %who  %who_ls 
%whos  %xdel  %xmode

Available cell magics:
%%!  %%bash  %%capture  %%file  %%perl  %%prun  %%ruby  %%script  %%sh  %%sx  %%system
%%timeit

Automagic is ON, % prefix IS NOT needed for line magics. 

>>>len?

Type:       builtin_function_or_method
String Form:
Namespace:  Python builtin
Docstring:
len(object) -> integer

Return the number of items of a sequence or mapping.

>>>str?

Type:       type
String Form:<type 'str'="">
Namespace:  Python builtin
Docstring:
str(object) -> string

Return a nice string representation of the object.

If the argument is a string, the return value is the same object. 

In [51]: import sys

In [52]: import os

In [53]: who
os  sys 

In [2]: !ping www.google.com

PING www.google.com (173.194.67.104): 56 data bytes
64 bytes from 173.194.67.104: icmp_seq=0 ttl=49 time=6.096 ms
64 bytes from 173.194.67.104: icmp_seq=1 ttl=49 time=5.963 ms
^C 

myDict={"name":"PythonForBeginners","acronym":"PFB","about":"Python Tutorials Website"}
print("The dictionary is:")
print(myDict)
print("The keys in the dictionary are:")
for x in myDict:
    print(x)

The dictionary is:
{'name': 'PythonForBeginners', 'acronym': 'PFB', 'about': 'Python Tutorials Website'}
The keys in the dictionary are:
name
acronym
about

myDict={"name":"PythonForBeginners","acronym":"PFB","about":"Python Tutorials Website"}
print("The dictionary is:")
print(myDict)
print("The values in the dictionary are:")
for x in myDict:
    print(myDict[x])

The dictionary is:
{'name': 'PythonForBeginners', 'acronym': 'PFB', 'about': 'Python Tutorials Website'}
The values in the dictionary are:
PythonForBeginners
PFB
Python Tutorials Website

myDict={"name":"PythonForBeginners","acronym":"PFB","about":"Python Tutorials Website"}
print("The dictionary is:")
print(myDict)
print("The keys in the dictionary are:")
keyList=myDict.keys()
for x in keyList:
    print(x)

The dictionary is:
{'name': 'PythonForBeginners', 'acronym': 'PFB', 'about': 'Python Tutorials Website'}
The keys in the dictionary are:
name
acronym
about

myDict={"name":"PythonForBeginners","acronym":"PFB","about":"Python Tutorials Website"}
print("The dictionary is:")
print(myDict)
print("The values in the dictionary are:")
keyList=myDict.keys()
for x in keyList:
    print(myDict[x])

The dictionary is:
{'name': 'PythonForBeginners', 'acronym': 'PFB', 'about': 'Python Tutorials Website'}
The values in the dictionary are:
PythonForBeginners
PFB
Python Tutorials Website

myDict={"name":"PythonForBeginners","acronym":"PFB","about":"Python Tutorials Website"}
print("The dictionary is:")
print(myDict)
print("The values in the dictionary are:")
valueList=myDict.values()
for x in valueList:
    print(x)

The dictionary is:
{'name': 'PythonForBeginners', 'acronym': 'PFB', 'about': 'Python Tutorials Website'}
The values in the dictionary are:
PythonForBeginners
PFB
Python Tutorials Website

myDict={"name":"PythonForBeginners","acronym":"PFB","about":"Python Tutorials Website"}
print("The dictionary is:")
print(myDict)
print("The items in the dictionary are:")
itemsList=myDict.items()
for x in itemsList:
    print(x)

The dictionary is:
{'name': 'PythonForBeginners', 'acronym': 'PFB', 'about': 'Python Tutorials Website'}
The items in the dictionary are:
('name', 'PythonForBeginners')
('acronym', 'PFB')
('about', 'Python Tutorials Website')

myDict={"name":"PythonForBeginners","acronym":"PFB","about":"Python Tutorials Website"}
print("The dictionary is:")
print(myDict)
itemList=myDict.items()
print("The key value pairs in the dictionary are:")
for x,y in itemList:
    print(x,end=":")
    print(y)

The dictionary is:
{'name': 'PythonForBeginners', 'acronym': 'PFB', 'about': 'Python Tutorials Website'}
The key value pairs in the dictionary are:
name:PythonForBeginners
acronym:PFB
about:Python Tutorials Website

myList = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
print("Elements of the list are:")
for element in myList:
    print(element) 

Elements of the list are:
1
2
3
4
5
6
7
8
9
10

myList = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
myIter = iter(myList)
print("list is:", myList)
print("Iterator for the list is:", myIter) 

list is: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
Iterator for the list is: <list_iterator object at 0x7f4c21734070>

myList = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
myIter = iter(myList)
print("list is:", myList)
print("Elements in the iterator are:")
for element in myIter:
    print(element)

list is: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
Elements in the iterator are:
1
2
3
4
5
6
7
8
9
10

myList = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
myIter = iter(myList)
print("list is:", myList)
print("Elements in the iterator are:")
try:
    print(myIter.__next__())
    print(myIter.__next__())
    print(myIter.__next__())
    print(myIter.__next__())
    print(myIter.__next__())
    print(myIter.__next__())
    print(myIter.__next__())
    print(myIter.__next__())
    print(myIter.__next__())
    print(myIter.__next__())
    print(myIter.__next__())
    print(myIter.__next__())
except StopIteration as e:
    print("All elements in the iterator already traversed. Raised exception", e)

list is: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
Elements in the iterator are:
1
2
3
4
5
6
7
8
9
10
All elements in the iterator already traversed. Raised exception 

myList = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
myIter = iter(myList)
print("list is:", myList)
print("Elements in the iterator are:")
try:
    print(next(myIter))
    print(next(myIter))
    print(next(myIter))
    print(next(myIter))
    print(next(myIter))
    print(next(myIter))
    print(next(myIter))
    print(next(myIter))
    print(next(myIter))
    print(next(myIter))
    print(next(myIter))
except StopIteration as e:
    print("All elements in the iterator already traversed. Raised exception", e) 

list is: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
Elements in the iterator are:
1
2
3
4
5
6
7
8
9
10
All elements in the iterator already traversed. Raised exception 

myList = range(0, 101)
myIter = iter(myList)
while True:
    try:
        user_input = int(input("Input an even number to get an output, 0 to exit:"))
        if user_input == 0:
            print("Good Bye")
            break
        elif user_input % 2 == 0:
            print("Very good. Here is an output for you.")
            print(next(myIter))
        else:
            print("Input an even number.")
            continue
    except StopIteration as e:
        print("All the output has been exhausted.") 

Input an even number to get an output, 0 to exit:1
Input an even number.
Input an even number to get an output, 0 to exit:2
Very good. Here is an output for you.
0
Input an even number to get an output, 0 to exit:4
Very good. Here is an output for you.
1
Input an even number to get an output, 0 to exit:3
Input an even number.
Input an even number to get an output, 0 to exit:6
Very good. Here is an output for you.
2
Input an even number to get an output, 0 to exit:0
Good Bye 

$ python
>>> 
>>> import keyword

>>> print keyword.kwlist

['and', 'as', 'assert', 'break', 'class', 'continue', 'def', 'del', 'elif', 'else',
'except', 'exec', 'finally', 'for', 'from', 'global', 'if', 'import', 'in', 'is',
'lambda', 'not', 'or', 'pass', 'print', 'raise', 'return', 'try', 'while', 'with',
'yield'] 

def square(n):
    return n ** 2

square = lambda n: n ** 2
print("Square of 4 is: ", square(4))

Square of 4 is:  16

def square(n):
    return n ** 2

print("Square of {} is:{} ".format(4, square(4)))
print("Square of {} is:{} ".format(3, square(3)))
print("Square of {} is:{} ".format(5, square(5)))
print("Square of {} is:{}".format(10, square(10)))

Square of 4 is:16 
Square of 3 is:9 
Square of 5 is:25 
Square of 10 is:100

def square(n):
    return n ** 2

print_square = lambda x, y: print("Square of {} is:{} ".format(x, y))
print_square(4, square(4))
print_square(3, square(3))
print_square(5, square(5))
print_square(10, square(10))

Square of 4 is:16 
Square of 3 is:9 
Square of 5 is:25 
Square of 10 is:100 

myList = [1, 23, 12, 45, 67, 344, 26]
print("The given list is:")
print(myList)
myList.sort()
print("The maximum element in the list is:", myList[-1])

The given list is:
[1, 23, 12, 45, 67, 344, 26]
The maximum element in the list is: 344

myList = [1, 23, 12, 45, 67, 344, 26]
print("The given list is:")
print(myList)
newList = sorted(myList)
print("The maximum element in the list is:", newList[-1])

The given list is:
[1, 23, 12, 45, 67, 344, 26]
The maximum element in the list is: 344

myList = [1, 23, 12, 45, 67, 344, 26]
print("The given list is:")
print(myList)
myVar = myList[0]
for element in myList:
    if element > myVar:
        myVar = element
print("The maximum element in the list is:", myVar)

The given list is:
[1, 23, 12, 45, 67, 344, 26]
The maximum element in the list is: 344

myList = [1, 23, 12, 45, 67, 344, 26]
print("The given list is:")
print(myList)
myVar = max(myList)
print("The maximum element in the list is:", myVar)

The given list is:
[1, 23, 12, 45, 67, 344, 26]
The maximum element in the list is: 344

import pandas as pd
import numpy as np
names=pd.read_csv("name.csv")
grades=pd.read_csv("grade.csv")
resultdf=names.merge(grades,how="left",on="Name")
print("The resultant dataframe is:")
print(resultdf)

The resultant dataframe is:
   Class_x  Roll_x      Name  Class_y  Roll_y Grade
0        1      11    Aditya      1.0    11.0     A
1        1      12     Chris      1.0    12.0    A+
2        1      13       Sam      NaN     NaN   NaN
3        2       1      Joel      2.0     1.0     B
4        2      22       Tom      2.0    22.0    B+
5        2      44  Samantha      NaN     NaN   NaN
6        3      33      Tina      3.0    33.0    A-
7        3      34       Amy      3.0    34.0     A 

import pandas as pd
import numpy as np
names=pd.read_csv("name.csv")
grades=pd.read_csv("grade.csv")
grades=grades.set_index("Name")
resultdf=names.join(grades,how="left",on="Name",lsuffix='_names', rsuffix='_grades')
print("The resultant dataframe is:")
print(resultdf)

The resultant dataframe is:
   Class_names  Roll_names      Name  Class_grades  Roll_grades Grade
0            1          11    Aditya           1.0         11.0     A
1            1          12     Chris           1.0         12.0    A+
2            1          13       Sam           NaN          NaN   NaN
3            2           1      Joel           2.0          1.0     B
4            2          22       Tom           2.0         22.0    B+
5            2          44  Samantha           NaN          NaN   NaN
6            3          33      Tina           3.0         33.0    A-
7            3          34       Amy           3.0         34.0     A

from queue import Queue

class BinaryTreeNode:
    def __init__(self, data):
        self.data = data
        self.leftChild = None
        self.rightChild = None

def levelorder(root):
    Q = Queue()
    Q.put(root)
    while (not Q.empty()):
        node = Q.get()
        if node == None:
            continue
        print(node.data)
        Q.put(node.leftChild)
        Q.put(node.rightChild)

def insert(root, newValue):
    # if binary search tree is empty, create a new node and declare it as root
    if root is None:
        root = BinaryTreeNode(newValue)
        return root
    # if newValue is less than value of data in root, add it to left subtree and proceed recursively
    if newValue < root.data:
        root.leftChild = insert(root.leftChild, newValue)
    else:
        # if newValue is greater than value of data in root, add it to right subtree and proceed recursively
        root.rightChild = insert(root.rightChild, newValue)
    return root

root = insert(None, 50)
insert(root, 20)
insert(root, 53)
insert(root, 11)
insert(root, 22)
insert(root, 52)
insert(root, 78)
print("Level Order traversal of the binary tree is:")
levelorder(root) 

Level Order traversal of the binary tree is:
50
20
53
11
22
52
78 

def LinearSearch(input_list: list, element: int):
    list_len = len(input_list)
    for i in range(list_len):
        if input_list[i] == element:
            return i
    return -1

myList = [1, 23, 45, 23, 34, 56, 12, 45, 67, 24]
print("Given list is:", myList)
position = LinearSearch(myList, 12)
print("Element 12 is at position:", position) 

Given list is: [1, 23, 45, 23, 34, 56, 12, 45, 67, 24]
Element 12 is at position: 6

class Node:
    def __init__(self,data):
        self.data=data
        self.next=None

class linkedList:
    def __init__(self):
        self.head=None

def insertAtBeginning(self,data):
        temp=Node(data)
        if self.head==None:
            self.head=temp
        else:
            temp.next=self.head
            self.head=temp

def insertAtEnd(self,data):
        temp=Node(data)
        if self.head==None:
            self.head=temp
        else:
            curr=self.head
            while curr.next!=None:
                curr=curr.next
            curr.next=temp

def insertAtGivenPosition(self,data,position):
        count=1
        curr=self.head
        while count<position-1 and curr!=None:
            curr=curr.next
            count+=1
        temp=Node(data)
        temp.next=curr.next
        curr.next=temp

def traverse(self):
        curr=self.head
        while curr!=None:
            print(curr.data)
            curr=curr.next

def delFromBeginning(self):
        try:
            if self.head==None:
                raise Exception("Empty Linked List")
            else:
                temp=self.head
                self.head=self.head.next
                del temp
        except Exception as e:
            print(str(e))

def delFromEnd(self):
        try:
            if self.head==None:
                raise Exception("Empty Linked List")
            else:
                curr=self.head
                prev=None
                while curr.next!=None:
                    prev=curr
                    curr=curr.next
                prev.next=curr.next
                del curr
        except Exception as e:
            print(str(e))

def delAtPos(self,position):
        try:
            if self.head==None:
                raise Exception("Empty Linked List")
            else:
                curr=self.head
                prev=None
                count=1
                while curr!=None and count<position:
                    prev=curr
                    curr=curr.next
                    count+=1
                prev.next=curr.next
                del curr
        except Exception as e:
            print(str(e))

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Sat Apr 24 18:28:15 2021

@author: aditya1117
"""

class Node:
    def __init__(self,data):
        self.data=data
        self.next=None
class linkedList:
    def __init__(self):
        self.head=None
    def insertAtBeginning(self,data):
        temp=Node(data)
        if self.head==None:
            self.head=temp
        else:
            temp.next=self.head
            self.head=temp
    def insertAtEnd(self,data):
        temp=Node(data)
        if self.head==None:
            self.head=temp
        else:
            curr=self.head
            while curr.next!=None:
                curr=curr.next
            curr.next=temp
    def insertAtGivenPosition(self,data,position):
        count=1
        curr=self.head
        while count<position-1 and curr!=None:
            curr=curr.next
            count+=1
        temp=Node(data)
        temp.next=curr.next
        curr.next=temp
    def traverse(self):
        curr=self.head
        while curr!=None:
            print(curr.data)
            curr=curr.next
    def delFromBeginning(self):
        try:
            if self.head==None:
                raise Exception("Empty Linked List")
            else:
                temp=self.head
                self.head=self.head.next
                del temp
        except Exception as e:
            print(str(e))
    def delFromEnd(self):
        try:
            if self.head==None:
                raise Exception("Empty Linked List")
            else:
                curr=self.head
                prev=None
                while curr.next!=None:
                    prev=curr
                    curr=curr.next
                prev.next=curr.next
                del curr
        except Exception as e:
            print(str(e))
    def delAtPos(self,position):
        try:
            if self.head==None:
                raise Exception("Empty Linked List")
            else:
                curr=self.head
                prev=None
                count=1
                while curr!=None and count<position:
                    prev=curr
                    curr=curr.next
                    count+=1
                prev.next=curr.next
                del curr
        except Exception as e:
            print(str(e)) 

# construct a basic list using range() and list comprehensions
# syntax
# [ expression for item in list ]
digits = [x for x in range(10)]

print(digits) 

[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

# create a list using a for loop
squares = []

for x in range(10):
    # raise x to the power of 2
    squares.append(x**2)

print(squares) 

[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]

# create a list using list comprehension
squares = [x**2 for x in range(10)]

print(squares) 

# create a list with list comprehensions
multiples_of_three = [ x*3 for x in range(10) ]

print(multiples_of_three) 

[0, 3, 6, 9, 12, 15, 18, 21, 24, 27]

even_numbers = [ x for x in range(1,20) if x % 2 == 0]

[2, 4, 6, 8, 10, 12, 14, 16, 18]

# a list of the names of popular authors
authors = ["Ernest Hemingway","Langston Hughes","Frank Herbert","Toni Morrison",
    "Emily Dickson","Stephen King"]

# create an acronym from the first letter of the author's names
letters = [ name[0] for name in authors ]
print(letters) 

['E', 'L', 'F', 'T', 'E', 'S']

# use list comprehension to print the letters in a string
letters = [ letter for letter in "20,000 Leagues Under The Sea"]

print(letters)

['2', '0', ',', '0', '0', '0', ' ', 'L', 'e', 'a', 'g', 'u', 'e', 's', ' ', 'U', 'n', 'd', 'e', 'r', ' ', 'T', 'h', 'e', ' ', 'S', 'e', 'a']

lower_case = [ letter.lower() for letter in ['A','B','C'] ]
upper_case = [ letter.upper() for letter in ['a','b','c'] ]

print(lower_case, upper_case) 

['a', 'b', 'c'] ['A', 'B', 'C']

# user data entered as name and phone number
user_data = "Elvis Presley 987-654-3210"
phone_number = [ x for x in user_data if x.isdigit()]

print(phone_number) 

['9', '8', '7', '6', '5', '4', '3', '2', '1', '0']

# open the file in read-only mode
file = open("dreams.txt", 'r')
poem = [ line for line in file ]

for line in poem:
    print(line) 

Hold fast to dreams

For if dreams die

Life is a broken-winged bird

That cannot fly.

-Langston Hughs 

# list comprehension with functions
# create a function that returns a number doubled
def double(x):
    return x*2

nums = [double(x) for x in range(1,10)]
print(nums) 

[2, 4, 6, 8, 10, 12, 14, 16, 18]

# add a filter so we only double even numbers
even_nums = [double(x) for x in range(1,10) if x%2 == 0]
print(even_nums) 

[4, 8, 12, 16]

nums = [x+y for x in [1,2,3] for y in [10,20,30]]
print(nums) 

[11, 21, 31, 12, 22, 32, 13, 23, 33]

import csv

listOfDict = [{'Name': 'Aditya', 'Roll': 1, 'Language': 'Python'}, {'Name': 'Sam', 'Roll': 2, 'Language': 'Java'},
              {'Name': 'Chris', 'Roll': 3, 'Language': 'C++'}, {'Name': 'Joel', 'Roll': 4, 'Language': 'TypeScript'}]
print("THe list of dictionaries is:")
print(listOfDict)
myFile = open('demo_file.csv', 'w')
writer = csv.writer(myFile)
writer.writerow(['Name', 'Roll', 'Language'])
for dictionary in listOfDict:
    writer.writerow(dictionary.values())
myFile.close()
myFile = open('demo_file.csv', 'r')
print("The content of the csv file is:")
print(myFile.read())
myFile.close()

THe list of dictionaries is:
[{'Name': 'Aditya', 'Roll': 1, 'Language': 'Python'}, {'Name': 'Sam', 'Roll': 2, 'Language': 'Java'}, {'Name': 'Chris', 'Roll': 3, 'Language': 'C++'}, {'Name': 'Joel', 'Roll': 4, 'Language': 'TypeScript'}]
The content of the csv file is:
Name,Roll,Language
Aditya,1,Python
Sam,2,Java
Chris,3,C++
Joel,4,TypeScript

import csv

listOfDict = [{'Name': 'Aditya', 'Roll': 1, 'Language': 'Python'}, {'Name': 'Sam', 'Roll': 2, 'Language': 'Java'},
              {'Name': 'Chris', 'Roll': 3, 'Language': 'C++'}, {'Name': 'Joel', 'Roll': 4, 'Language': 'TypeScript'}]
print("THe list of dictionaries is:")
print(listOfDict)
myFile = open('demo_file.csv', 'w')
writer = csv.DictWriter(myFile, fieldnames=['Name', 'Roll', 'Language'])
writer.writeheader()
writer.writerows(listOfDict)
myFile.close()
myFile = open('demo_file.csv', 'r')
print("The content of the csv file is:")
print(myFile.read())
myFile.close()

THe list of dictionaries is:
[{'Name': 'Aditya', 'Roll': 1, 'Language': 'Python'}, {'Name': 'Sam', 'Roll': 2, 'Language': 'Java'}, {'Name': 'Chris', 'Roll': 3, 'Language': 'C++'}, {'Name': 'Joel', 'Roll': 4, 'Language': 'TypeScript'}]
The content of the csv file is:
Name,Roll,Language
Aditya,1,Python
Sam,2,Java
Chris,3,C++
Joel,4,TypeScript

import pandas as pd

listOfDict = [{'Name': 'Aditya', 'Roll': 1, 'Language': 'Python'}, {'Name': 'Sam', 'Roll': 2, 'Language': 'Java'},
              {'Name': 'Chris', 'Roll': 3, 'Language': 'C++'}, {'Name': 'Joel', 'Roll': 4, 'Language': 'TypeScript'}]
print("THe list of dictionaries is:")
print(listOfDict)
df = pd.DataFrame(listOfDict)
print("The dataframe is:")
print(df)

THe list of dictionaries is:
[{'Name': 'Aditya', 'Roll': 1, 'Language': 'Python'}, {'Name': 'Sam', 'Roll': 2, 'Language': 'Java'}, {'Name': 'Chris', 'Roll': 3, 'Language': 'C++'}, {'Name': 'Joel', 'Roll': 4, 'Language': 'TypeScript'}]
The dataframe is:
     Name  Roll    Language
0  Aditya     1      Python
1     Sam     2        Java
2   Chris     3         C++
3    Joel     4  TypeScript

import pandas as pd

listOfDict = [{'Name': 'Aditya', 'Roll': 1, 'Language': 'Python'}, {'Name': 'Sam', 'Roll': 2, 'Language': 'Java'},
              {'Name': 'Chris', 'Roll': 3, 'Language': 'C++'}, {'Name': 'Joel', 'Roll': 4, 'Language': 'TypeScript'}]
print("THe list of dictionaries is:")
print(listOfDict)
df = pd.DataFrame.from_dict(listOfDict)
print("The dataframe is:")
print(df)

THe list of dictionaries is:
[{'Name': 'Aditya', 'Roll': 1, 'Language': 'Python'}, {'Name': 'Sam', 'Roll': 2, 'Language': 'Java'}, {'Name': 'Chris', 'Roll': 3, 'Language': 'C++'}, {'Name': 'Joel', 'Roll': 4, 'Language': 'TypeScript'}]
The dataframe is:
     Name  Roll    Language
0  Aditya     1      Python
1     Sam     2        Java
2   Chris     3         C++
3    Joel     4  TypeScript

import pandas as pd

listOfDict = [{'Name': 'Aditya', 'Roll': 1, 'Language': 'Python'}, {'Name': 'Sam', 'Roll': 2, 'Language': 'Java'},
              {'Name': 'Chris', 'Roll': 3, 'Language': 'C++'}, {'Name': 'Joel', 'Roll': 4, 'Language': 'TypeScript'}]
print("THe list of dictionaries is:")
print(listOfDict)
df = pd.DataFrame.from_records(listOfDict)
print("The dataframe is:")
print(df)

THe list of dictionaries is:
[{'Name': 'Aditya', 'Roll': 1, 'Language': 'Python'}, {'Name': 'Sam', 'Roll': 2, 'Language': 'Java'}, {'Name': 'Chris', 'Roll': 3, 'Language': 'C++'}, {'Name': 'Joel', 'Roll': 4, 'Language': 'TypeScript'}]
The dataframe is:
     Name  Roll    Language
0  Aditya     1      Python
1     Sam     2        Java
2   Chris     3         C++
3    Joel     4  TypeScript

myList=[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]

list1 = [1, 2, 3, 4, 5]
print("The first list is:", list1)
list2 = [12, 13, 23]
print("The second list is:", list2)
list3 = [10, 20, 30]
print("The third list is:", list3)
list4 = [11, 22, 33]
print("The fourth list is:", list4)
list5 = [12, 24, 36]
print("The fifth list is:", list5)
myList = [list1, list2, list3, list4, list5]
print("The list of lists is:")
print(myList)

The first list is: [1, 2, 3, 4, 5]
The second list is: [12, 13, 23]
The third list is: [10, 20, 30]
The fourth list is: [11, 22, 33]
The fifth list is: [12, 24, 36]
The list of lists is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]

list1 = [1, 2, 3, 4, 5]
print("The first list is:", list1)
list2 = [12, 13, 23]
print("The second list is:", list2)
list3 = [10, 20, 30]
print("The third list is:", list3)
list4 = [11, 22, 33]
print("The fourth list is:", list4)
list5 = [12, 24, 36]
print("The fifth list is:", list5)
myList = []
myList.append(list1)
myList.append(list2)
myList.append(list3)
myList.append(list4)
myList.append(list5)
print("The list of lists is:")
print(myList)

The first list is: [1, 2, 3, 4, 5]
The second list is: [12, 13, 23]
The third list is: [10, 20, 30]
The fourth list is: [11, 22, 33]
The fifth list is: [12, 24, 36]
The list of lists is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]] 

myList = []
for i in range(3):
    tempList = []
    for j in range(3):
        element = i + j
        tempList.append(element)
    myList.append(tempList)
print("The list of lists is:")
print(myList)

The list of lists is:
[[0, 1, 2], [1, 2, 3], [2, 3, 4]]

myList = [[i+j for i in range(3)] for j in range(3)]
print("The list of lists is:")
print(myList)

The list of lists is:
[[0, 1, 2], [1, 2, 3], [2, 3, 4]]

myList = [1, 2, 3, 4, 5]
print("The list is:")
print(myList)
print("The first item of the list is:")
print(myList[0])

The list is:
[1, 2, 3, 4, 5]
The first item of the list is:
1

myList = [1, 2, 3, 4, 5]
print("The list is:")
print(myList)
print("The last item of the list is:")
print(myList[-1])

The list is:
[1, 2, 3, 4, 5]
The last item of the list is:
5 

myList = [[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
print("The list of lists is:")
print(myList)
print("The first item of the nested list is:")
print(myList[0])

The list of lists is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
The first item of the nested list is:
[1, 2, 3, 4, 5]

myList = [[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
print("The list of lists is:")
print(myList)
print("The last item of the nested list is:")
print(myList[-1])

The list of lists is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
The last item of the nested list is:
[12, 24, 36]

myList = [[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
print("The list of lists is:")
print(myList)
print("The third element of the second inner list is:")
print(myList[1][2])

The list of lists is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
The third element of the second inner list is:
23

myList = [[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
for inner_list in myList:
    print(inner_list)

[1, 2, 3, 4, 5]
[12, 13, 23]
[10, 20, 30]
[11, 22, 33]
[12, 24, 36]

myList = [[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
for inner_list in myList:
    for element in inner_list:
        print(element, end=",")
    print("")

1,2,3,4,5,
12,13,23,
10,20,30,
11,22,33,
12,24,36,

myList = [[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
print("The original list is:")
print(myList)
myList.pop()
print("The modified list is:")
print(myList)

The original list is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
The modified list is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33]]

myList = [[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
print("The original list is:")
print(myList)
myList.pop(1)
print("The modified list is:")
print(myList)

The original list is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
The modified list is:
[[1, 2, 3, 4, 5], [10, 20, 30], [11, 22, 33], [12, 24, 36]]

myList = [[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
print("The original list is:")
print(myList)
myList.remove([1, 2, 3, 4, 5])
print("The modified list is:")
print(myList)

The original list is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
The modified list is:
[[12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]

myList = [[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
print("The original list is:")
print(myList)
outputList = []
for inner_list in myList:
    for element in inner_list:
        outputList.append(element)
print("The flattened list is:")
print(outputList) 

The original list is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
The flattened list is:
[1, 2, 3, 4, 5, 12, 13, 23, 10, 20, 30, 11, 22, 33, 12, 24, 36]

myList = [[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
print("The original list is:")
print(myList)
outputList = [x for l in myList for x in l]
print("The flattened list is:")
print(outputList)

The original list is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
The flattened list is:
[1, 2, 3, 4, 5, 12, 13, 23, 10, 20, 30, 11, 22, 33, 12, 24, 36]

myList = [[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
print("The original list is:")
print(myList)
outputList = []
listlen = len(myList)
for i in range(listlen):
    outputList.append(myList[listlen - 1 - i])
print("The reversed list is:")
print(outputList) 

The original list is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
The reversed list is:
[[12, 24, 36], [11, 22, 33], [10, 20, 30], [12, 13, 23], [1, 2, 3, 4, 5]]

myList = [[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
print("The original list is:")
print(myList)
myList.reverse()
print("The reversed list is:")
print(myList)

The original list is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
The reversed list is:
[[12, 24, 36], [11, 22, 33], [10, 20, 30], [12, 13, 23], [1, 2, 3, 4, 5]]

myList = [[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
print("The original list is:")
print(myList)
outputList = []
listlen = len(myList)
for i in range(listlen):
    tempList = []
    currList = myList[listlen - 1 - i]
    innerLen = len(currList)
    for j in range(innerLen):
        tempList.append(currList[innerLen - 1 - j])
    outputList.append(tempList)

print("The reversed list is:")
print(outputList)

The original list is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
The reversed list is:
[[36, 24, 12], [33, 22, 11], [30, 20, 10], [23, 13, 12], [5, 4, 3, 2, 1]]

myList = [[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
print("The original list is:")
print(myList)
outputList = []
listlen = len(myList)
for i in range(listlen):
    myList[listlen - 1 - i].reverse()
    outputList.append(myList[listlen - 1 - i])

print("The reversed list is:")
print(outputList)

The original list is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
The reversed list is:
[[36, 24, 12], [33, 22, 11], [30, 20, 10], [23, 13, 12], [5, 4, 3, 2, 1]]

myList = [[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
print("The original list is:")
print(myList)
myList.sort()
print("The sorted list is:")
print(myList)

The original list is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
The sorted list is:
[[1, 2, 3, 4, 5], [10, 20, 30], [11, 22, 33], [12, 13, 23], [12, 24, 36]]

myList = [[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
print("The original list is:")
print(myList)
myList.sort(key=lambda x: x[2])
print("The sorted list is:")
print(myList)

The original list is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
The sorted list is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]

myList = [[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
print("The original list is:")
print(myList)
myList.sort(key=lambda x: x[-1])
print("The sorted list is:")
print(myList)

The original list is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
The sorted list is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]

myList = [[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
print("The original list is:")
print(myList)
myList.sort(key=len)
print("The sorted list is:")
print(myList)

The original list is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
The sorted list is:
[[12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36], [1, 2, 3, 4, 5]]

myList = [[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
print("The original list is:")
print(myList)
outputList = sorted(myList)
print("The sorted list is:")
print(outputList)

The original list is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
The sorted list is:
[[1, 2, 3, 4, 5], [10, 20, 30], [11, 22, 33], [12, 13, 23], [12, 24, 36]]

myList = [[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
print("The original list is:")
print(myList)
outputList = sorted(myList, key=lambda x: x[2])
print("The sorted list is:")
print(outputList)

The original list is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
The sorted list is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]

myList = [[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
print("The original list is:")
print(myList)
outputList = sorted(myList, key=lambda x: x[-1])
print("The sorted list is:")
print(outputList)

The original list is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
The sorted list is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]

myList = [[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
print("The original list is:")
print(myList)
outputList = sorted(myList, key=len)
print("The sorted list is:")
print(outputList)

The original list is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
The sorted list is:
[[12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36], [1, 2, 3, 4, 5]]

list1 = [[1, 2, 3, 4, 5], [12, 13, 23]]
list2 = [[10, 20, 30], [11, 22, 33], [12, 24, 36]]
print("The first list is:")
print(list1)
print("The second list is:")
print(list2)
print("The concatenated list is:")
myList = list1 + list2
print(myList)

The first list is:
[[1, 2, 3, 4, 5], [12, 13, 23]]
The second list is:
[[10, 20, 30], [11, 22, 33], [12, 24, 36]]
The concatenated list is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]] 

import copy
myList = [[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
print("The original list is:")
print(myList)
outputList = copy.copy(myList)
print("The copied list is:")
print(outputList)

The original list is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
The copied list is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]

import copy
myList = [[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
print("The original list is:")
print(myList)
outputList = copy.deepcopy(myList)
print("The copied list is:")
print(outputList)

The original list is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]
The copied list is:
[[1, 2, 3, 4, 5], [12, 13, 23], [10, 20, 30], [11, 22, 33], [12, 24, 36]]

myList = ["1", "2", "3", "4", "5"]
output_list = []
for element in myList:
    value = int(element)
    output_list.append(value)
print("The input list is:", myList)
print("The output list is:", output_list)

The input list is: ['1', '2', '3', '4', '5']
The output list is: [1, 2, 3, 4, 5]

myList = ["1", "2", "3", "4", "5", "PFB"]
output_list = []
for element in myList:
    value = int(element)
    output_list.append(value)
print("The input list is:", myList)
print("The output list is:", output_list) 

Traceback (most recent call last):
  File "/home/aditya1117/PycharmProjects/pythonProject/string1.py", line 4, in <module>
    value = int(element)
ValueError: invalid literal for int() with base 10: 'PFB'

myList = ["1", "2", "3", "4", "5", "PFB"]
output_list = []
for element in myList:
    try:
        value = int(element)
        output_list.append(value)
    except ValueError:
        print("{} cannot be converted to integer.".format(element))
print("The input list is:", myList)
print("The output list is:", output_list)

PFB cannot be converted to integer.
The input list is: ['1', '2', '3', '4', '5', 'PFB']
The output list is: [1, 2, 3, 4, 5]

myList = ["1", "2", "3", "4", "5"]
output_list = [int(element) for element in myList]
print("The input list is:", myList)
print("The output list is:", output_list)

The input list is: ['1', '2', '3', '4', '5']
The output list is: [1, 2, 3, 4, 5]

myList = ["1", "2", "3", "4", "5", "PFB"]
output_list = [int(element) for element in myList]
print("The input list is:", myList)
print("The output list is:", output_list)

Traceback (most recent call last):
  File "/home/aditya1117/PycharmProjects/pythonProject/string1.py", line 2, in <module>
    output_list = [int(element) for element in myList]
  File "/home/aditya1117/PycharmProjects/pythonProject/string1.py", line 2, in <listcomp>
    output_list = [int(element) for element in myList]
ValueError: invalid literal for int() with base 10: 'PFB' 

myList = ["1", "2", "3", "4", "5"]
output_list = list(map(int, myList))
print("The input list is:", myList)
print("The output list is:", output_list)

The input list is: ['1', '2', '3', '4', '5']
The output list is: [1, 2, 3, 4, 5]

myList = ["1", "2", "3", "4", "5", "PFB"]
output_list = list(map(int, myList))
print("The input list is:", myList)
print("The output list is:", output_list)

Traceback (most recent call last):
  File "/home/aditya1117/PycharmProjects/pythonProject/string1.py", line 2, in <module>
    output_list = list(map(int, myList))
ValueError: invalid literal for int() with base 10: 'PFB'

 s = ['h','e','l','l','o']	#create a list
s.append('d')         		#append to end of list
len(s)                		#number of items in list
s.pop(2)              		#delete an item in the middle
s.sort()               		#sorting the list
s.reverse()           		#reversing the list
s.extend(['w','o'])    		#grow list
s.insert(1,2)         		#insert into list
s.remove('d')           	#remove first item in list with value e
s.pop()               		#remove last item in the list
s.pop(1)              		#remove indexed value from list
s.count('o')            	#search list and return number of instances found
s = range(0,10)          	#create a list over range 
s = range(0,10,2)        	#create a list over range with start index and increment 

# Import the modules
import sys
import random

ans = True

while ans:
    question = raw_input("Ask the magic 8 ball a question: (press enter to quit) ")

    answers = random.randint(1,8)

    if question == "":
        sys.exit()

    elif answers == 1:
        print "It is certain"

    elif answers == 2:
        print "Outlook good"

    elif answers == 3:
        print "You may rely on it"

    elif answers == 4:
        print "Ask again later"

    elif answers == 5:
        print "Concentrate and ask again"

    elif answers == 6:
        print "Reply hazy, try again"

    elif answers == 7:
        print "My reply is no"

    elif answers == 8:
        print "My sources say no" 

$ pip freeze

 $ sudo pip install virtualenvwrapper 

 $ mkvirtualenv testground 

 New python executable in testground/bin/python
Installing Setuptools.........done.
Installing Pip..............done.
virtualenvwrapper.user_scripts creating /home/yourname/.virtualenvs/testground/bin/predeactivate
virtualenvwrapper.user_scripts creating /home/yourname/.virtualenvs/testground/bin/postdeactivate
virtualenvwrapper.user_scripts creating /home/yourname/.virtualenvs/testground/bin/preactivate
virtualenvwrapper.user_scripts creating /home/yourname/.virtualenvs/testground/bin/postactivate
virtualenvwrapper.user_scripts creating /home/yourname/.virtualenvs/testground/bin/get_env_details

(testground)[[email protected]](/cdn-cgi/l/email-protection):~$ 

$ pip freeze
argparse==1.2.1
wsgiref==0.1.2 

 $ pip install Pillow==2.2.2 

$ mkvirtualenv coolapp

 ...................done.
virtualenvwrapper.user_scripts creating /home/yourname/.virtualenvs/coolapp/bin/predeactivate
virtualenvwrapper.user_scripts creating /home/yourname/.virtualenvs/coolapp/bin/postdeactivate
virtualenvwrapper.user_scripts creating /home/yourname/.virtualenvs/coolapp/bin/preactivate
virtualenvwrapper.user_scripts creating /home/yourname/.virtualenvs/coolapp/bin/postactivate
virtualenvwrapper.user_scripts creating /home/yourname/.virtualenvs/coolapp/bin/get_env_details
(coolapp)[[email protected]](/cdn-cgi/l/email-protection):~$ 

$ workon testground
(testground)[[email protected]](/cdn-cgi/l/email-protection):~$ 

 $ mkvirtualenv anotherenv --no-site-packages 

 $ rmvirtualenv coolapp

Removing coolapp... 

 $lsvirtualenv 

 $ lssitepackages

#can result in this:
easy_install.py   Pillow-2.2.2-py2.7.egg-info  pkg_resources.pyc
easy_install.pyc  pip                          setuptools
_markerlib        pip-1.4.1-py2.7.egg-info     setuptools-0.9.8-py2.7.egg-info
PIL               pkg_resources.py 

 Class  Roll      Name
0       1    11    Aditya
1       1    12     Chris
2       1    13       Sam
3       1    14      Joel
4       1    15       Tom
5       1    16  Samantha
6       1    17     Pablo
7       1    20      Tina
8       1    24       Amy
9       1    30    Justin
10      1    31      Karl

 Roll  Marks Grade
0    11     85     A
1    12     95     A
2    13     75     B
3    14     75     B
4    16     78     B
5    15     55     C
6    19     75     B
7    20     72     B
8    24     92     A
9    25     95     A

 Roll  Marks Grade  Class      Name
0    11     85     A      1    Aditya
1    12     95     A      1     Chris
2    13     75     B      1       Sam
3    14     75     B      1      Joel
4    16     78     B      1  Samantha
5    15     55     C      1       Tom
6    20     72     B      1      Tina
7    24     92     A      1       Amy

pd.merge(df1,df2, on) 

import numpy as np
import pandas as pd
df1=pd.read_csv("grade_with_roll1.csv")
print("First dataframe is:")
print(df1)
df2=pd.read_csv("name_data1.csv")
print("second dataframe is:")
print(df2)
df3=pd.merge(df1,df2,left_on="Roll", right_on="Roll")
print("Merged dataframe is:")
print(df3)

First dataframe is:
   Roll  Marks Grade
0    11     85     A
1    12     95     A
2    13     75     B
3    14     75     B
4    16     78     B
5    15     55     C
6    19     75     B
7    20     72     B
8    24     92     A
9    25     95     A
second dataframe is:
    Class  Roll      Name
0       1    11    Aditya
1       1    12     Chris
2       1    13       Sam
3       1    14      Joel
4       1    15       Tom
5       1    16  Samantha
6       1    17     Pablo
7       1    20      Tina
8       1    24       Amy
9       1    30    Justin
10      1    31      Karl
Merged dataframe is:
   Roll  Marks Grade  Class      Name
0    11     85     A      1    Aditya
1    12     95     A      1     Chris
2    13     75     B      1       Sam
3    14     75     B      1      Joel
4    16     78     B      1  Samantha
5    15     55     C      1       Tom
6    20     72     B      1      Tina
7    24     92     A      1       Amy

import numpy as np
import pandas as pd
df1=pd.read_csv("grade_with_roll1.csv")
print("First dataframe is:")
print(df1)
df2=pd.read_csv("name_data1.csv")
print("second dataframe is:")
print(df2)
df3=pd.merge(df1,df2,how="outer",left_on="Roll", right_on="Roll",suffixes=("_left","_right"))
print("Merged dataframe is:")
print(df3)

First dataframe is:
   Roll  Marks Grade
0    11     85     A
1    12     95     A
2    13     75     B
3    14     75     B
4    16     78     B
5    15     55     C
6    19     75     B
7    20     72     B
8    24     92     A
9    25     95     A
second dataframe is:
    Class  Roll      Name
0       1    11    Aditya
1       1    12     Chris
2       1    13       Sam
3       1    14      Joel
4       1    15       Tom
5       1    16  Samantha
6       1    17     Pablo
7       1    20      Tina
8       1    24       Amy
9       1    30    Justin
10      1    31      Karl
Merged dataframe is:
    Roll  Marks Grade  Class      Name
0     11   85.0     A    1.0    Aditya
1     12   95.0     A    1.0     Chris
2     13   75.0     B    1.0       Sam
3     14   75.0     B    1.0      Joel
4     16   78.0     B    1.0  Samantha
5     15   55.0     C    1.0       Tom
6     19   75.0     B    NaN       NaN
7     20   72.0     B    1.0      Tina
8     24   92.0     A    1.0       Amy
9     25   95.0     A    NaN       NaN
10    17    NaN   NaN    1.0     Pablo
11    30    NaN   NaN    1.0    Justin
12    31    NaN   NaN    1.0      Karl

import numpy as np
import pandas as pd
df1=pd.read_csv("grade_with_roll1.csv")
print("First dataframe is:")
print(df1)
df2=pd.read_csv("name_data1.csv")
print("second dataframe is:")
print(df2)
df3=pd.merge(df1,df2,how="left",left_on="Roll", right_on="Roll",suffixes=("_left","_right"))
print("Merged dataframe is:")
print(df3)

First dataframe is:
   Roll  Marks Grade
0    11     85     A
1    12     95     A
2    13     75     B
3    14     75     B
4    16     78     B
5    15     55     C
6    19     75     B
7    20     72     B
8    24     92     A
9    25     95     A
second dataframe is:
    Class  Roll      Name
0       1    11    Aditya
1       1    12     Chris
2       1    13       Sam
3       1    14      Joel
4       1    15       Tom
5       1    16  Samantha
6       1    17     Pablo
7       1    20      Tina
8       1    24       Amy
9       1    30    Justin
10      1    31      Karl
Merged dataframe is:
   Roll  Marks Grade  Class      Name
0    11     85     A    1.0    Aditya
1    12     95     A    1.0     Chris
2    13     75     B    1.0       Sam
3    14     75     B    1.0      Joel
4    16     78     B    1.0  Samantha
5    15     55     C    1.0       Tom
6    19     75     B    NaN       NaN
7    20     72     B    1.0      Tina
8    24     92     A    1.0       Amy
9    25     95     A    NaN       NaN

import numpy as np
import pandas as pd
df1=pd.read_csv("grade_with_roll1.csv")
print("First dataframe is:")
print(df1)
df2=pd.read_csv("name_data1.csv")
print("second dataframe is:")
print(df2)
df3=pd.merge(df1,df2,how="right",left_on="Roll", right_on="Roll",suffixes=("_left","_right"))
print("Merged dataframe is:")
print(df3)

First dataframe is:
   Roll  Marks Grade
0    11     85     A
1    12     95     A
2    13     75     B
3    14     75     B
4    16     78     B
5    15     55     C
6    19     75     B
7    20     72     B
8    24     92     A
9    25     95     A
second dataframe is:
    Class  Roll      Name
0       1    11    Aditya
1       1    12     Chris
2       1    13       Sam
3       1    14      Joel
4       1    15       Tom
5       1    16  Samantha
6       1    17     Pablo
7       1    20      Tina
8       1    24       Amy
9       1    30    Justin
10      1    31      Karl
Merged dataframe is:
    Roll  Marks Grade  Class      Name
0     11   85.0     A      1    Aditya
1     12   95.0     A      1     Chris
2     13   75.0     B      1       Sam
3     14   75.0     B      1      Joel
4     15   55.0     C      1       Tom
5     16   78.0     B      1  Samantha
6     17    NaN   NaN      1     Pablo
7     20   72.0     B      1      Tina
8     24   92.0     A      1       Amy
9     30    NaN   NaN      1    Justin
10    31    NaN   NaN      1      Karl

dict1={1:1,2:4,3:9}
print("First dictionary is:")
print(dict1)
dict2={4:16,5:25,6:36}
print("Second dictionary is:")
print(dict2)
for key,value in dict2.items():
    dict1[key]=value
print("Merged dictionary is:")
print(dict1)

First dictionary is:
{1: 1, 2: 4, 3: 9}
Second dictionary is:
{4: 16, 5: 25, 6: 36}
Merged dictionary is:
{1: 1, 2: 4, 3: 9, 4: 16, 5: 25, 6: 36}

dict1={1:1,2:4,3:9}
print("First dictionary is:")
print(dict1)
dict2={4:16,5:25,6:36}
print("Second dictionary is:")
print(dict2)
while dict2:
    key,value=dict2.popitem()
    dict1[key]=value
print("Merged dictionary is:")
print(dict1)

First dictionary is:
{1: 1, 2: 4, 3: 9}
Second dictionary is:
{4: 16, 5: 25, 6: 36}
Merged dictionary is:
{1: 1, 2: 4, 3: 9, 6: 36, 5: 25, 4: 16}

dict1={1:1,2:4,3:9}
print("First dictionary is:")
print(dict1)
dict2={4:16,5:25,6:36}
print("Second dictionary is:")
print(dict2)
keylist=dict2.keys()
for key in keylist:
    dict1[key]=dict2[key]
print("Merged dictionary is:")
print(dict1)

First dictionary is:
{1: 1, 2: 4, 3: 9}
Second dictionary is:
{4: 16, 5: 25, 6: 36}
Merged dictionary is:
{1: 1, 2: 4, 3: 9, 4: 16, 5: 25, 6: 36}

dict1={1:1,2:4,3:9}
print("First dictionary is:")
print(dict1)
dict2={4:16,5:25,6:36}
print("Second dictionary is:")
print(dict2)
dict1.update(dict2)
print("Merged dictionary is:")
print(dict1)

First dictionary is:
{1: 1, 2: 4, 3: 9}
Second dictionary is:
{4: 16, 5: 25, 6: 36}
Merged dictionary is:
{1: 1, 2: 4, 3: 9, 4: 16, 5: 25, 6: 36}

dict1={1:1,2:4,3:9}
print("First dictionary is:")
print(dict1)
dict2={4:16,5:25,6:36}
print("Second dictionary is:")
print(dict2)
mergedDict={**dict1,**dict2}
print("Merged dictionary is:")
print(mergedDict)

First dictionary is:
{1: 1, 2: 4, 3: 9}
Second dictionary is:
{4: 16, 5: 25, 6: 36}
Merged dictionary is:
{1: 1, 2: 4, 3: 9, 4: 16, 5: 25, 6: 36}

list1=[1,2,3,4]
list2=[5,6,7,8]
print("First list is:")
print(list1)
print("Second list is:")
print(list2)
for i in list2:
    list1.append(i)
print("Merged list is:")
print(list1)

First list is:
[1, 2, 3, 4]
Second list is:
[5, 6, 7, 8]
Merged list is:
[1, 2, 3, 4, 5, 6, 7, 8]

list1=[1,2,3,4]
list2=[5,6,7,8]
print("First list is:")
print(list1)
print("Second list is:")
print(list2)
while list2:
    temp=list2.pop()
    list1.append(temp)
print("Merged list is:")
print(list1)

First list is:
[1, 2, 3, 4]
Second list is:
[5, 6, 7, 8]
Merged list is:
[1, 2, 3, 4, 8, 7, 6, 5]

list1=[1,2,3,4]
list2=[5,6,7,8]
print("First list is:")
print(list1)
print("Second list is:")
print(list2)
combined_list=[list1,list2]
merged_list=[item for sublist in combined_list for item in sublist]
print("Merged list is:")
print(merged_list)

First list is:
[1, 2, 3, 4]
Second list is:
[5, 6, 7, 8]
Merged list is:
[1, 2, 3, 4, 5, 6, 7, 8]

list1=[1,2,3,4]
list2=[5,6,7,8]
print("First list is:")
print(list1)
print("Second list is:")
print(list2)
merged_list=list1+list2
print("Merged list is:")
print(merged_list)

First list is:
[1, 2, 3, 4]
Second list is:
[5, 6, 7, 8]
Merged list is:
[1, 2, 3, 4, 5, 6, 7, 8]

list1=[1,2,3,4]
list2=[5,6,7,8]
print("First list is:")
print(list1)
print("Second list is:")
print(list2)
merged_list=[*list1,*list2]
print("Merged list is:")
print(merged_list)

First list is:
[1, 2, 3, 4]
Second list is:
[5, 6, 7, 8]
Merged list is:
[1, 2, 3, 4, 5, 6, 7, 8]

list1=[1,2,3,4]
list2=[5,6,7,8]
print("First list is:")
print(list1)
print("Second list is:")
print(list2)
list1.extend(list2)
print("Merged list is:")
print(list1)

First list is:
[1, 2, 3, 4]
Second list is:
[5, 6, 7, 8]
Merged list is:
[1, 2, 3, 4, 5, 6, 7, 8]

import itertools
list1=[1,2,3,4]
list2=[5,6,7,8]
print("First list is:")
print(list1)
print("Second list is:")
print(list2)
merged_list=list(itertools.chain(list1,list2))
print("Merged list is:")
print(merged_list)

First list is:
[1, 2, 3, 4]
Second list is:
[5, 6, 7, 8]
Merged list is:
[1, 2, 3, 4, 5, 6, 7, 8]

import sys
program_name = sys.argv[0]
arguments = sys.argv[1:]
count = len(arguments)

import sys
for x in sys.argv:
     print "Argument: ", x

 len(sys.argv) , checks how many arguments that have been entered. 

len(sys.argv) != 2 just checks whether you entered at least two elements 

import sys
if len (sys.argv) != 2 :
    print "Usage: python ex.py "
    sys.exit (1)

 >python ex.py
Argument:  ex.py

>python ex.py hello
Argument:  ex.py
Argument:  hello

>python ex.py hello world
Argument:  ex.py
Argument:  hello
Argument:  world 

color=(100,125,130)

color={"red":100, "green":125, "blue": 130}

from collections import namedtuple

Color = namedtuple("Color", ["red", "green", "blue"])

color=Color(100,125,130)

from collections import namedtuple

Color = namedtuple("Color", ["red", "green", "blue"])
color = Color(100, 125, 130)

print("The namedtuple is:", color)
print("The red value is:", color.red)
print("The green value is:", color.green)
print("The blue value is:", color.blue) 

The namedtuple is: Color(red=100, green=125, blue=130)
The red value is: 100
The green value is: 125
The blue value is: 130

from collections import namedtuple

Color = namedtuple("Color", ["red", "green", "blue"])
color = Color(100, 125, 130)

print("The namedtuple is:", color)
print("The fields of the namedtuple are:", color._fields)

The namedtuple is: Color(red=100, green=125, blue=130)
The fields of the namedtuple are: ('red', 'green', 'blue')

from collections import namedtuple

Color = namedtuple("Color", ["red", "green", "blue"])
color = Color(100, 125, 130)

print("The original namedtuple is:", color)
color = color._replace(red=200)
print("The modified namedtuple is:", color) 

The original namedtuple is: Color(red=100, green=125, blue=130)
The modified namedtuple is: Color(red=200, green=125, blue=130) 

new_list = [expression for item in list]

new_list = [[expression for item in list] for item in list] 

# create a list of lists
matrix = [[0,1,2],[0,1,2],[0,1,2]]
print(matrix) 

[[0, 1, 2], [0, 1, 2], [0, 1, 2]]

matrix = []
for y in range(3):
    matrix.append([])
    for x in range(3):
        matrix[y].append(x)

print(matrix) 

[[0, 1, 2], [0, 1, 2], [0, 1, 2]]

matrix = [[x for x in range(3)] for y in range(3)]
print(matrix)

[[0, 1, 2], [0, 1, 2], [0, 1, 2]]

tic_tac_toe_board = [[' ' for x in range(3)] for y in range(3)]

def PrintMatrix(matrix):
    for row in range(len(matrix)):
        print(matrix[row])

PrintMatrix(tic_tac_toe_board) 

[' ', ' ', ' ']
[' ', ' ', ' ']
[' ', ' ', ' '] 

tic_tac_toe_board[1][1] = 'X'
PrintMatrix(tic_tac_toe_board) 

[' ', ' ', ' ']
[' ', 'X', ' ']
[' ', ' ', ' '] 

matrix = [[x+(y*3) for x in range(3)] for y in range(3)]

print(matrix) 

[[0, 1, 2], [3, 4, 5], [6, 7, 8]]

matrix = [[1,2,3],
          [4,5,6],
          [7,8,9]]

transposed = [[x[y] for x in matrix] for y in range(len(matrix))]

print(transposed) 

[1, 4, 7]
[2, 5, 8]
[3, 6, 9] 

matrix = [x for x in range(1,10) if x%2 == 0]

print(matrix) 

[2, 4, 6, 8]]

matrix = [[x for x in range(1,10) if x%2 == 0] for y in range(2)]

print(matrix) 

[[2, 4, 6, 8], [2, 4, 6, 8]]

matrix = [[1,2,3],
          [4,5,6],
          [7,8,9]]

# welcome to Flatland
flat = [x for row in matrix for x in row]

print(flat) 

[1, 2, 3, 4, 5, 6, 7, 8, 9]

list = []
for row in matrix:
    for x in row:
        list.append(x)

print(list) 

[1, 2, 3, 4, 5, 6, 7, 8, 9]

myFile = open("sample.txt", "r")
text = myFile.read()
print("The content of the file is:")
print(text)
numberOfLines = 0
for character in text:
    if character == "\n":
        numberOfLines = numberOfLines + 1
print("The number of lines in the file is:")
print(numberOfLines) 

The content of the file is:
This is line 1.
This is line 2.
This is line 3.
This is line 4.

The number of lines in the file is:
4

myFile = open("sample.txt", "r")
text = myFile.read()
print("The content of the file is:")
print(text)
text_list = text.split("\n")
numberOfLines = len(text_list)
print("The number of lines in the file is:")
print(numberOfLines)

The content of the file is:
This is line 1.
This is line 2.
This is line 3.
This is line 4.
The number of lines in the file is:
4

myFile = open("sample.txt", "r")
text_list = myFile.readlines()
numberOfLines = len(text_list)
print("The number of lines in the file is:")
print(numberOfLines)

The number of lines in the file is:
4

import numpy as np
arr1=np.array([1,2,3,4,5,6,7])
print("The original array is:",arr1)
number=10
arr=arr1+10
print("The modified array is:",arr)

The original array is: [1 2 3 4 5 6 7]
The modified array is: [11 12 13 14 15 16 17]

import numpy as np
arr1=np.array([1,2,3,4,5,6,7])
print("The original array is:",arr1)
number=10
arr=arr1*10
print("The modified array is:",arr)

The original array is: [1 2 3 4 5 6 7]
The modified array is: [10 20 30 40 50 60 70]

import numpy as np
arr1=np.array([1,2,3,4,5,6,7])
print("The first array is:",arr1)
arr2=np.array([8,9,10,11,12,13,14])
print("The second array is:",arr2)
arr=arr1+arr2
print("The output array is:",arr)

The first array is: [1 2 3 4 5 6 7]
The second array is: [ 8  9 10 11 12 13 14]
The output array is: [ 9 11 13 15 17 19 21]

import numpy as np
arr1=np.array([1,2,3,4,5,6,7])
print("The first array is:",arr1)
arr2=np.array([8,9,10,11,12,13])
print("The second array is:",arr2)
arr=arr1+arr2
print("The output array is:",arr)

The first array is: [1 2 3 4 5 6 7]
The second array is: [ 8  9 10 11 12 13]
ValueError: operands could not be broadcast together with shapes (7,) (6,) 

import numpy as np
arr1=np.array([1,2,3,4,5,6,7])
print("The first array is:",arr1)
arr2=np.array([8,9,10,11,12,13,14])
print("The second array is:",arr2)
arr=arr1*arr2
print("The output array is:",arr)

The first array is: [1 2 3 4 5 6 7]
The second array is: [ 8  9 10 11 12 13 14]
The output array is: [ 8 18 30 44 60 78 98]

import numpy as np
arr1=np.array([1,2,3,4,5,6,7])
print("The array is:",arr1)
number=5
arr=arr1>number
print("The output array is:",arr)

The array is: [1 2 3 4 5 6 7]
The output array is: [False False False False False  True  True]

import numpy as np
arr1=np.array([1,2,3,4,5,6,7])
print("The first array is:",arr1)
arr2=np.array([8,9,10,11,12,13,14])
print("The second array is:",arr2)
arr=arr1>arr2
print("The output array is:",arr)

The first array is: [1 2 3 4 5 6 7]
The second array is: [ 8  9 10 11 12 13 14]
The output array is: [False False False False False False False]

import numpy as np
arr1=np.array([1,2,3,4,5,6,7])
print("The array is:",arr1)
max_element=arr1.max()
print("The maximum element is:",max_element)

The array is: [1 2 3 4 5 6 7]
The maximum element is: 7

import numpy as np
arr1=np.array([[1,2,3,4,5,6,7],[8,9,10,11,12,13,14]])
print("The array is:",arr1)
max_element=arr1.max()
print("The maximum element is:",max_element)

The array is: [[ 1  2  3  4  5  6  7]
 [ 8  9 10 11 12 13 14]]
The maximum element is: 14

import numpy as np
arr1=np.array([1,2,3,4,5,6,7])
print("The array is:",arr1)
min_element=arr1.min()
print("The minimum element is:",min_element)

The array is: [1 2 3 4 5 6 7]
The minimum element is: 1

import numpy as np
arr1=np.array([1,2,3,4,5,6,7])
print("The array is:",arr1)
max_element=arr1.argmax()
print("The index of maximum element is:",max_element)

The array is: [1 2 3 4 5 6 7]
The index of maximum element is: 6

import numpy as np
arr1=np.array([1,2,3,4,5,6,7])
print("The array is:",arr1)
min_element=arr1.argmin()
print("The index of minimum element is:",min_element)

The array is: [1 2 3 4 5 6 7]
The index of minimum element is: 0

import numpy as np
arr1=np.array([[8,9,10,11,12,13,14],[1,2,3,4,5,6,7]])
print("The array is:",arr1)
max_element=arr1.argmax()
print("The index of maximum element is:",max_element)

The array is: [[ 8  9 10 11 12 13 14]
 [ 1  2  3  4  5  6  7]]
The index of maximum element is: 6 

import numpy as np
arr1=np.array([1,2,17,4,21,6,7])
print("The original array is:",arr1)
arr1.sort()
print("The sorted array is:",arr1)

The original array is: [ 1  2 17  4 21  6  7]
The sorted array is: [ 1  2  4  6  7 17 21]

import numpy as np
arr1=np.array([[8,9,12,11,27,34,14],[55,2,15,4,22,6,7]])
print("The original array is:",arr1)
arr1.sort()
print("The sorted array is:",arr1)

The original array is: [[ 8  9 12 11 27 34 14]
 [55  2 15  4 22  6  7]]
The sorted array is: [[ 8  9 11 12 14 27 34]
 [ 2  4  6  7 15 22 55]]

mySlice=myArray[start_index:end_index:interval]

import numpy as np
myArr=np.array([1,2,17,4,21,6,7,12,13,14])
print("The original array is:",myArr)
mySlice=myArr[2:6:1]
print("The slice is:",mySlice)

The original array is: [ 1  2 17  4 21  6  7 12 13 14]
The slice is: [17  4 21  6] 

import numpy as np
myArr=np.array([1,2,17,4,21,6,7,12,13,14])
print("The original array is:",myArr)
mySlice=myArr[2:6]
print("The slice is:",mySlice)

The original array is: [ 1  2 17  4 21  6  7 12 13 14]
The slice is: [17  4 21  6]

import numpy as np
myArr=np.array([1,2,17,4,21,6,7,12,13,14])
print("The original array is:",myArr)
mySlice=myArr[:6:1]
print("The slice is:",mySlice)

The original array is: [ 1  2 17  4 21  6  7 12 13 14]
The slice is: [ 1  2 17  4 21  6]

import numpy as np
myArr=np.array([1,2,17,4,21,6,7,12,13,14])
print("The original array is:",myArr)
mySlice=myArr[2::1]
print("The slice is:",mySlice)

The original array is: [ 1  2 17  4 21  6  7 12 13 14]
The slice is: [17  4 21  6  7 12 13 14]

import numpy as np
myArr=np.array([1,2,17,4,21,6,7,12,13,14])
print("The original array is:",myArr)
mySlice=myArr[2::2]
print("The slice is:",mySlice)

The original array is: [ 1  2 17  4 21  6  7 12 13 14]
The slice is: [17 21  7 13]

mySlice=myArray[start_row:end_row:row_interval,start_column:end_column:column_interval]

import numpy as np
myArr=np.arange(100).reshape((10,10))
print("The original array is:")
print(myArr)
mySlice=myArr[0:4:1,1:5:1]
print("The slice is:")
print(mySlice)

The original array is: 
[[ 0  1  2  3  4  5  6  7  8  9]
 [10 11 12 13 14 15 16 17 18 19]
 [20 21 22 23 24 25 26 27 28 29]
 [30 31 32 33 34 35 36 37 38 39]
 [40 41 42 43 44 45 46 47 48 49]
 [50 51 52 53 54 55 56 57 58 59]
 [60 61 62 63 64 65 66 67 68 69]
 [70 71 72 73 74 75 76 77 78 79]
 [80 81 82 83 84 85 86 87 88 89]
 [90 91 92 93 94 95 96 97 98 99]]
The slice is: 
[[ 1  2  3  4]
 [11 12 13 14]
 [21 22 23 24]
 [31 32 33 34]]

import numpy as np
myArr=np.arange(100).reshape((10,10))
print("The original array is:")
print(myArr)
mySlice=myArr[::1,1:5:1]
print("The slice is:")
print(mySlice)

The original array is:
[[ 0  1  2  3  4  5  6  7  8  9]
 [10 11 12 13 14 15 16 17 18 19]
 [20 21 22 23 24 25 26 27 28 29]
 [30 31 32 33 34 35 36 37 38 39]
 [40 41 42 43 44 45 46 47 48 49]
 [50 51 52 53 54 55 56 57 58 59]
 [60 61 62 63 64 65 66 67 68 69]
 [70 71 72 73 74 75 76 77 78 79]
 [80 81 82 83 84 85 86 87 88 89]
 [90 91 92 93 94 95 96 97 98 99]]
The slice is:
[[ 1  2  3  4]
 [11 12 13 14]
 [21 22 23 24]
 [31 32 33 34]
 [41 42 43 44]
 [51 52 53 54]
 [61 62 63 64]
 [71 72 73 74]
 [81 82 83 84]
 [91 92 93 94]]

import numpy as np
myArr=np.arange(100).reshape((10,10))
print("The original array is:")
print(myArr)
mySlice=myArr[0:4:1,::1]
print("The slice is:")
print(mySlice)

The original array is:
[[ 0  1  2  3  4  5  6  7  8  9]
 [10 11 12 13 14 15 16 17 18 19]
 [20 21 22 23 24 25 26 27 28 29]
 [30 31 32 33 34 35 36 37 38 39]
 [40 41 42 43 44 45 46 47 48 49]
 [50 51 52 53 54 55 56 57 58 59]
 [60 61 62 63 64 65 66 67 68 69]
 [70 71 72 73 74 75 76 77 78 79]
 [80 81 82 83 84 85 86 87 88 89]
 [90 91 92 93 94 95 96 97 98 99]]
The slice is:
[[ 0  1  2  3  4  5  6  7  8  9]
 [10 11 12 13 14 15 16 17 18 19]
 [20 21 22 23 24 25 26 27 28 29]
 [30 31 32 33 34 35 36 37 38 39]]

import numpy as np
myArr=np.arange(100).reshape((10,10))
print("The original array is:")
print(myArr)
mySlice=myArr[:4:1,2:5:1]
print("The slice is:")
print(mySlice)

The original array is:
[[ 0  1  2  3  4  5  6  7  8  9]
 [10 11 12 13 14 15 16 17 18 19]
 [20 21 22 23 24 25 26 27 28 29]
 [30 31 32 33 34 35 36 37 38 39]
 [40 41 42 43 44 45 46 47 48 49]
 [50 51 52 53 54 55 56 57 58 59]
 [60 61 62 63 64 65 66 67 68 69]
 [70 71 72 73 74 75 76 77 78 79]
 [80 81 82 83 84 85 86 87 88 89]
 [90 91 92 93 94 95 96 97 98 99]]
The slice is:
[[ 2  3  4]
 [12 13 14]
 [22 23 24]
 [32 33 34]]

import numpy as np
myArr=np.arange(100).reshape((10,10))
print("The original array is:")
print(myArr)
mySlice=myArr[3::1,2:5:1]
print("The slice is:")
print(mySlice)

The original array is:
[[ 0  1  2  3  4  5  6  7  8  9]
 [10 11 12 13 14 15 16 17 18 19]
 [20 21 22 23 24 25 26 27 28 29]
 [30 31 32 33 34 35 36 37 38 39]
 [40 41 42 43 44 45 46 47 48 49]
 [50 51 52 53 54 55 56 57 58 59]
 [60 61 62 63 64 65 66 67 68 69]
 [70 71 72 73 74 75 76 77 78 79]
 [80 81 82 83 84 85 86 87 88 89]
 [90 91 92 93 94 95 96 97 98 99]]
The slice is:
[[32 33 34]
 [42 43 44]
 [52 53 54]
 [62 63 64]
 [72 73 74]
 [82 83 84]
 [92 93 94]]

import numpy as np
myArr=np.arange(100).reshape((10,10))
print("The original array is:")
print(myArr)
mySlice=myArr[1:4:1,:5:1]
print("The slice is:")
print(mySlice)

The original array is:
[[ 0  1  2  3  4  5  6  7  8  9]
 [10 11 12 13 14 15 16 17 18 19]
 [20 21 22 23 24 25 26 27 28 29]
 [30 31 32 33 34 35 36 37 38 39]
 [40 41 42 43 44 45 46 47 48 49]
 [50 51 52 53 54 55 56 57 58 59]
 [60 61 62 63 64 65 66 67 68 69]
 [70 71 72 73 74 75 76 77 78 79]
 [80 81 82 83 84 85 86 87 88 89]
 [90 91 92 93 94 95 96 97 98 99]]
The slice is:
[[10 11 12 13 14]
 [20 21 22 23 24]
 [30 31 32 33 34]] 

import numpy as np
myArr=np.arange(100).reshape((10,10))
print("The original array is:")
print(myArr)
mySlice=myArr[3::1,4::1]
print("The slice is:")
print(mySlice)

The original array is:
[[ 0  1  2  3  4  5  6  7  8  9]
 [10 11 12 13 14 15 16 17 18 19]
 [20 21 22 23 24 25 26 27 28 29]
 [30 31 32 33 34 35 36 37 38 39]
 [40 41 42 43 44 45 46 47 48 49]
 [50 51 52 53 54 55 56 57 58 59]
 [60 61 62 63 64 65 66 67 68 69]
 [70 71 72 73 74 75 76 77 78 79]
 [80 81 82 83 84 85 86 87 88 89]
 [90 91 92 93 94 95 96 97 98 99]]
The slice is:
[[34 35 36 37 38 39]
 [44 45 46 47 48 49]
 [54 55 56 57 58 59]
 [64 65 66 67 68 69]
 [74 75 76 77 78 79]
 [84 85 86 87 88 89]
 [94 95 96 97 98 99]] 

import numpy as np
myArr=np.arange(100).reshape((10,10))
print("The original array is:")
print(myArr)
mySlice=myArr[3::2,4::3]
print("The slice is:")
print(mySlice)

The original array is:
[[ 0  1  2  3  4  5  6  7  8  9]
 [10 11 12 13 14 15 16 17 18 19]
 [20 21 22 23 24 25 26 27 28 29]
 [30 31 32 33 34 35 36 37 38 39]
 [40 41 42 43 44 45 46 47 48 49]
 [50 51 52 53 54 55 56 57 58 59]
 [60 61 62 63 64 65 66 67 68 69]
 [70 71 72 73 74 75 76 77 78 79]
 [80 81 82 83 84 85 86 87 88 89]
 [90 91 92 93 94 95 96 97 98 99]]
The slice is:
[[34 37]
 [54 57]
 [74 77]
 [94 97]]

import numpy as np
myArr=np.arange(100).reshape((10,10))
print("The original array is:")
print(myArr)
mySlice=myArr[3::2,4::3]
print("The slice is:")
print(mySlice)
mySlice+=100
print("The original array is:")
print(myArr)

The original array is:
[[ 0  1  2  3  4  5  6  7  8  9]
 [10 11 12 13 14 15 16 17 18 19]
 [20 21 22 23 24 25 26 27 28 29]
 [30 31 32 33 34 35 36 37 38 39]
 [40 41 42 43 44 45 46 47 48 49]
 [50 51 52 53 54 55 56 57 58 59]
 [60 61 62 63 64 65 66 67 68 69]
 [70 71 72 73 74 75 76 77 78 79]
 [80 81 82 83 84 85 86 87 88 89]
 [90 91 92 93 94 95 96 97 98 99]]
The slice is:
[[34 37]
 [54 57]
 [74 77]
 [94 97]]
The original array is:
[[  0   1   2   3   4   5   6   7   8   9]
 [ 10  11  12  13  14  15  16  17  18  19]
 [ 20  21  22  23  24  25  26  27  28  29]
 [ 30  31  32  33 134  35  36 137  38  39]
 [ 40  41  42  43  44  45  46  47  48  49]
 [ 50  51  52  53 154  55  56 157  58  59]
 [ 60  61  62  63  64  65  66  67  68  69]
 [ 70  71  72  73 174  75  76 177  78  79]
 [ 80  81  82  83  84  85  86  87  88  89]
 [ 90  91  92  93 194  95  96 197  98  99]]

import numpy as np
arr1=np.arange(20)
print("The first array is:")
print(arr1)
arr2=arr1.reshape((4,5))
print("The reshaped array is:")
print(arr2)

The first array is:
[ 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19]
The reshaped array is:
[[ 0  1  2  3  4]
 [ 5  6  7  8  9]
 [10 11 12 13 14]
 [15 16 17 18 19]]

import numpy as np
arr1=np.arange(20)
print("The first array is:")
print(arr1)
arr2=np.reshape(arr1,(4,5))
print("The reshaped array is:")
print(arr2)

The first array is:
[ 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19]
The reshaped array is:
[[ 0  1  2  3  4]
 [ 5  6  7  8  9]
 [10 11 12 13 14]
 [15 16 17 18 19]]

import numpy as np
arr1=np.arange(20)
print("The first array is:")
print(arr1)
arr2=np.reshape(arr1,(4,7))
print("The reshaped array is:")
print(arr2)

ValueError: cannot reshape array of size 20 into shape (4,7)

import numpy as np
arr1=np.arange(20)
print("The first array is:")
print(arr1)
arr2=np.reshape(arr1,(4,5))
print("The reshaped array is:")
print(arr2)
arr2+=100
print("The first array is:")
print(arr1)

The first array is:
[ 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19]
The reshaped array is:
[[ 0  1  2  3  4]
 [ 5  6  7  8  9]
 [10 11 12 13 14]
 [15 16 17 18 19]]
The first array is:
[100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117
 118 119]

import numpy as np
arr1=np.arange(20).reshape(4,5)
print("The first array is:")
print(arr1)
arr2=np.reshape(arr1,-1)
print("The flattened array is:")
print(arr2)

The first array is:
[[ 0  1  2  3  4]
 [ 5  6  7  8  9]
 [10 11 12 13 14]
 [15 16 17 18 19]]
The flattened array is:
[ 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19]

import numpy as np
arr1=np.arange(20).reshape(4,5)
print("The first array is:")
print(arr1)
arr2=arr1.flatten()
print("The flattened array is:")
print(arr2)

The first array is:
[[ 0  1  2  3  4]
 [ 5  6  7  8  9]
 [10 11 12 13 14]
 [15 16 17 18 19]]
The flattened array is:
[ 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19]

import numpy as np
arr1=np.arange(20).reshape(4,5)
print("The first array is:")
print(arr1)
arr2=arr1.flatten()
print("The flattened array is:")
print(arr2)
arr2+=50
print("The first array is:")
print(arr1)

The first array is:
[[ 0  1  2  3  4]
 [ 5  6  7  8  9]
 [10 11 12 13 14]
 [15 16 17 18 19]]
The flattened array is:
[ 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19]
The first array is:
[[ 0  1  2  3  4]
 [ 5  6  7  8  9]
 [10 11 12 13 14]
 [15 16 17 18 19]]

import numpy as np
arr1=np.arange(20).reshape(4,5)
print("The first array is:")
print(arr1)
arr2=arr1.reshape(-1)
print("The flattened array is:")
print(arr2)
arr2+=50
print("The first array is:")
print(arr1)

The first array is:
[[ 0  1  2  3  4]
 [ 5  6  7  8  9]
 [10 11 12 13 14]
 [15 16 17 18 19]]
The flattened array is:
[ 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19]
The first array is:
[[50 51 52 53 54]
 [55 56 57 58 59]
 [60 61 62 63 64]
 [65 66 67 68 69]]

import numpy as np
arr1=np.arange(20)
print("The first array is:")
print(arr1)
arr2=arr1.copy()
print("The copied array is:")
print(arr2)

The first array is:
[ 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19]
The copied array is:
[ 0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19]

import os
print "-" * 30
print "os.stat    = status of a file 	" , os.stat('/usr/bin/vi')
print "-" * 30 

 import os

os.system()		Executing a shell command
os.environ()		Get the users environment
os.getcwd()	 	Returns the current working directory.
os.getgid()		Return the real group id of the current process. 
os.getuid() 		Return the current process’s user id.
os.getpid() 		Returns the real process ID of the current process.
os.uname()		Return information identifying the current OS.
os.chroot(path)		Change the root directory of the current process to path
os.listdir(path)	Return a list of the entries in the directory by path.
os.mkdir(path)		Create a directory named path with numeric mode mode
os.makedirs(path)	Recursive directory creation function
os.remove(path)		Remove (delete) the file path
os.removedirs(path)	Remove directories recursively
os.rename(src, dst)	Rename the file or directory src to dst
os.rmdir(path)		Remove (delete) the directory path 

 import fnmatch
import os

rootPath = '/'
pattern = '*.mp3'

for root, dirs, files in os.walk(rootPath):
    for filename in fnmatch.filter(files, pattern):
        print( os.path.join(root, filename)) 

import fnmatch
import os

images = ['*.jpg', '*.jpeg', '*.png', '*.tif', '*.tiff']
matches = []

for root, dirnames, filenames in os.walk("C:\"):
    for extensions in images:
        for filename in fnmatch.filter(filenames, extensions):
            matches.append(os.path.join(root, filename)) 

num1=1
num2=2
num3=3
myTuple=(num1,num2,num3)

 num1=1
num2=2
num3=3
myList=[num1,num2,num3]

num1=1
num2=2
num3=3
*num,=num1,num2,num3

num1=1
num2=2
num3=3
*num,myNum=num1,num2,num3

def sumOfNumbers(num1,num2,*nums):
    temp=num1+num2
    for i in nums:
        temp=temp+i
    return temp

name="Joseph Robinette Biden Jr"
first_name, *rest_name=name.split()
print("Full Name:")
print(name)
print("First Name:")
print(first_name)
print("Rest Parts of Name:")
print(rest_name)

Full Name:
Joseph Robinette Biden Jr
First Name:
Joseph
Rest Parts of Name:
['Robinette', 'Biden', 'Jr']

 print("First Tuple is:")
tuple1=(1,2,3)
print(tuple1)
print("Second Tuple is:")
tuple2=(4,5,6)
print(tuple2)
print("Merged tuple is:")
myTuple=(*tuple1,*tuple2)
print(myTuple) 

First Tuple is:
(1, 2, 3)
Second Tuple is:
(4, 5, 6)
Merged tuple is:
(1, 2, 3, 4, 5, 6)

print("First List is:")
list1=[1,2,3]
print(list1)
print("Second List is:")
list2=[4,5,6]
print(list2)
print("Merged List is:")
myList=[*list1,*list2]
print(myList)

First List is:
[1, 2, 3]
Second List is:
[4, 5, 6]
Merged List is:
[1, 2, 3, 4, 5, 6]

print("First Dictionary is:")
dict1={1:1,2:4,3:9}
print(dict1)
print("Second Dictionary is:")
dict2={4:16,5:25,6:36}
print(dict2)
print("Merged Dictionary is:")
myDict={**dict1,**dict2}
print(myDict)

First Dictionary is:
{1: 1, 2: 4, 3: 9}
Second Dictionary is:
{4: 16, 5: 25, 6: 36}
Merged Dictionary is:
{1: 1, 2: 4, 3: 9, 4: 16, 5: 25, 6: 36}

import pandas as pd
list1=[1,2,3]
list2=[3,55,34]
list3=[12,32,45]
myList=[list1,list2,list3]
myDf=pd.DataFrame(myList,columns=["A", "B", "C"])
print("The dataframe is:")
print(myDf)
print("The index is:")
index=list(myDf.index)
print(index)

The dataframe is:
    A   B   C
0   1   2   3
1   3  55  34
2  12  32  45
The index is:
[0, 1, 2]

import pandas as pd
list1=[1,2,3]
list2=[3,55,34]
list3=[12,32,45]
myList=[list1,list2,list3]
myDf=pd.DataFrame(myList,columns=["A", "B", "C"],index=[101,102,103])
print("The dataframe is:")
print(myDf)
print("The index is:")
index=list(myDf.index)
print(index)

The dataframe is:
      A   B   C
101   1   2   3
102   3  55  34
103  12  32  45
The index is:
[101, 102, 103]

import pandas as pd
list1=[1,2,3]
list2=[3,55,34]
list3=[12,32,45]
myList=[list1,list2,list3]
myDf=pd.DataFrame(myList,columns=["A", "B", "C"],index=[101,102,103,104])
print("The dataframe is:")
print(myDf)
print("The index is:")
index=list(myDf.index)
print(index)

ValueError: Length of values (3) does not match length of index (4)

myDf=pd.read_csv("samplefile.csv",index_col="Class")
print("The dataframe is:")
print(myDf)
print("The index is:")
index=list(myDf.index)
print(index)

The dataframe is:
       Roll      Name
Class                
1        11    Aditya
1        12     Chris
1        13       Sam
2         1      Joel
2        22       Tom
2        44  Samantha
3        33      Tina
3        34       Amy
The index is:
[1, 1, 1, 2, 2, 2, 3, 3]

myDf=pd.read_csv("samplefile.csv",index_col=0)
print("The dataframe is:")
print(myDf)
print("The index is:")
index=list(myDf.index)
print(index)

The dataframe is:
       Roll      Name
Class                
1        11    Aditya
1        12     Chris
1        13       Sam
2         1      Joel
2        22       Tom
2        44  Samantha
3        33      Tina
3        34       Amy
The index is:
[1, 1, 1, 2, 2, 2, 3, 3]

myDf=pd.read_csv("samplefile.csv")
print("The dataframe is:")
myDf.index=[101,102,103,104,105,106,107,108]
print(myDf)
print("The index is:")
index=list(myDf.index)
print(index)

The dataframe is:
     Class  Roll      Name
101      1    11    Aditya
102      1    12     Chris
103      1    13       Sam
104      2     1      Joel
105      2    22       Tom
106      2    44  Samantha
107      3    33      Tina
108      3    34       Amy
The index is:
[101, 102, 103, 104, 105, 106, 107, 108] 

myDf=pd.read_csv("samplefile.csv")
print("The dataframe is:")
myDf=myDf.set_index("Class")
print(myDf)
print("The index is:")
index=list(myDf.index)
print(index)

The dataframe is:
       Roll      Name
Class                
1        11    Aditya
1        12     Chris
1        13       Sam
2         1      Joel
2        22       Tom
2        44  Samantha
3        33      Tina
3        34       Amy
The index is:
[1, 1, 1, 2, 2, 2, 3, 3]

myDf=pd.read_csv("samplefile.csv")
print("The dataframe is:")
myDf=myDf.set_index("Class")
print(myDf)
print("The index is:")
index=list(myDf.index)
print(index)
print("The modified dataframe is:")
newDf=myDf.set_index("Roll")
print(newDf)
print("The index is:")
index=list(newDf.index)
print(index)

The dataframe is:
       Roll      Name
Class                
1        11    Aditya
1        12     Chris
1        13       Sam
2         1      Joel
2        22       Tom
2        44  Samantha
3        33      Tina
3        34       Amy
The index is:
[1, 1, 1, 2, 2, 2, 3, 3]
The modified dataframe is:
          Name
Roll          
11      Aditya
12       Chris
13         Sam
1         Joel
22         Tom
44    Samantha
33        Tina
34         Amy
The index is:
[11, 12, 13, 1, 22, 44, 33, 34]

myDf=pd.read_csv("samplefile.csv")
print("The dataframe is:")
myDf=myDf.set_index("Class")
print(myDf)
print("The index is:")
index=list(myDf.index)
print(index)
print("The modified dataframe is:")
myDf.index=[101, 102, 103, 104, 105, 106, 107, 108]
print(myDf)
print("The index is:")
index=list(myDf.index)
print(index)

The dataframe is:
       Roll      Name
Class                
1        11    Aditya
1        12     Chris
1        13       Sam
2         1      Joel
2        22       Tom
2        44  Samantha
3        33      Tina
3        34       Amy
The index is:
[1, 1, 1, 2, 2, 2, 3, 3]
The modified dataframe is:
     Roll      Name
101    11    Aditya
102    12     Chris
103    13       Sam
104     1      Joel
105    22       Tom
106    44  Samantha
107    33      Tina
108    34       Amy
The index is:
[101, 102, 103, 104, 105, 106, 107, 108]

myDf=pd.read_csv("samplefile.csv")
print("The dataframe is:")
myDf=myDf.set_index("Class")
print(myDf)
print("The index is:")
index=list(myDf.index)
print(index)
print("The modified dataframe is:")
myDf["Class"]=myDf.index
myDf.index=[101, 102, 103, 104, 105, 106, 107, 108]
print(myDf)
print("The index is:")
index=list(myDf.index)
print(index)

The dataframe is:
       Roll      Name
Class                
1        11    Aditya
1        12     Chris
1        13       Sam
2         1      Joel
2        22       Tom
2        44  Samantha
3        33      Tina
3        34       Amy
The index is:
[1, 1, 1, 2, 2, 2, 3, 3]
The modified dataframe is:
     Roll      Name  Class
101    11    Aditya      1
102    12     Chris      1
103    13       Sam      1
104     1      Joel      2
105    22       Tom      2
106    44  Samantha      2
107    33      Tina      3
108    34       Amy      3
The index is:
[101, 102, 103, 104, 105, 106, 107, 108]

myDf=pd.read_csv("samplefile.csv",index_col=["Class","Roll"])
print("The dataframe is:")
print(myDf)
print("The index is:")
index=list(myDf.index)
print(index)

The dataframe is:
                Name
Class Roll          
1     11      Aditya
      12       Chris
      13         Sam
2     1         Joel
      22         Tom
      44    Samantha
3     33        Tina
      34         Amy
The index is:
[(1, 11), (1, 12), (1, 13), (2, 1), (2, 22), (2, 44), (3, 33), (3, 34)]

myDf=pd.read_csv("samplefile.csv",index_col=[0,1])
print("The dataframe is:")
print(myDf)
print("The index is:")
index=list(myDf.index)
print(index)

The dataframe is:
                Name
Class Roll          
1     11      Aditya
      12       Chris
      13         Sam
2     1         Joel
      22         Tom
      44    Samantha
3     33        Tina
      34         Amy
The index is:
[(1, 11), (1, 12), (1, 13), (2, 1), (2, 22), (2, 44), (3, 33), (3, 34)]

myDf=pd.read_csv("samplefile.csv")
print("The dataframe is:")
myDf=myDf.set_index(["Class","Roll"])
print(myDf)
print("The index is:")
index=list(myDf.index)
print(index)

The dataframe is:
                Name
Class Roll          
1     11      Aditya
      12       Chris
      13         Sam
2     1         Joel
      22         Tom
      44    Samantha
3     33        Tina
      34         Amy
The index is:
[(1, 11), (1, 12), (1, 13), (2, 1), (2, 22), (2, 44), (3, 33), (3, 34)] 

myDf=pd.read_csv("samplefile.csv",index_col=[0,1])
print("The dataframe is:")
print(myDf)
print("The index is:")
index=list(myDf.index)
print(index)
myDf=myDf.reset_index()
print("The modified dataframe is:")
print(myDf)
print("The index is:")
index=list(myDf.index)
print(index)

The dataframe is:
                Name
Class Roll          
1     11      Aditya
      12       Chris
      13         Sam
2     1         Joel
      22         Tom
      44    Samantha
3     33        Tina
      34         Amy
The index is:
[(1, 11), (1, 12), (1, 13), (2, 1), (2, 22), (2, 44), (3, 33), (3, 34)]
The modified dataframe is:
   Class  Roll      Name
0      1    11    Aditya
1      1    12     Chris
2      1    13       Sam
3      2     1      Joel
4      2    22       Tom
5      2    44  Samantha
6      3    33      Tina
7      3    34       Amy
The index is:
[0, 1, 2, 3, 4, 5, 6, 7]

import pandas as pd
names = ['Aditya', 'Chris', 'Joel']
print("The input list is:")
print(names)
print("The series is:")
mySeries=pd.Series(names)
print(mySeries)

The input list is:
['Aditya', 'Chris', 'Joel']
The series is:
0    Aditya
1     Chris
2      Joel
dtype: object 

import pandas as pd
names = ['Aditya', 'Chris', 'Joel']
print("The input list is:")
print(names)
print("The series is:")
mySeries=pd.Series(names, index=["A","B", "C"])
print(mySeries)

The input list is:
['Aditya', 'Chris', 'Joel']
The series is:
A    Aditya
B     Chris
C      Joel
dtype: object

import pandas as pd
names = ['Aditya', 'Chris', 'Joel']
print("The input list is:")
print(names)
print("The series is:")
mySeries=pd.Series(names, index=["A","B", "C", "D"])
print(mySeries)

The input list is:
['Aditya', 'Chris', 'Joel']
The series is:

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
/tmp/ipykernel_6004/861141107.py in <module>
      4 print(names)
      5 print("The series is:")
----> 6 mySeries=pd.Series(names, index=["A","B", "C", "D"])
      7 print(mySeries)

ValueError: Length of values (3) does not match length of index (4)

import pandas as pd
names = ['Aditya', 'Chris', 'Joel']
print("The input list is:")
print(names)
print("Series before index creation:")
mySeries=pd.Series(names)
print(mySeries)
mySeries.index=["A","B", "C"]
print("Series after index creation:")
print(mySeries)

The input list is:
['Aditya', 'Chris', 'Joel']
Series before index creation:
0    Aditya
1     Chris
2      Joel
dtype: object
Series after index creation:
A    Aditya
B     Chris
C      Joel
dtype: object

import pandas as pd
names = {"A":'Aditya', "B":'Chris', "C":'Joel'}
print("The input dictionary is:")
print(names)
print("The series is:")
mySeries=pd.Series(names)
print(mySeries)

The input dictionary is:
{'A': 'Aditya', 'B': 'Chris', 'C': 'Joel'}
The series is:
A    Aditya
B     Chris
C      Joel
dtype: object

import pandas as pd
names = {'Aditya', 'Chris', 'Joel'}
print("The input set is:")
print(names)
print("The series is:")
mySeries=pd.Series(names)
print(mySeries)

The input set is:
{'Joel', 'Aditya', 'Chris'}
The series is:

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
/tmp/ipykernel_6004/4101083988.py in <module>
      4 print(names)
      5 print("The series is:")
----> 6 mySeries=pd.Series(names)
      7 print(mySeries)

TypeError: 'set' type is unordered 

import pandas as pd
names = [1,2,3,4]
print("The input list is:")
print(names)
print("The series is:")
mySeries=pd.Series(names)
print(mySeries)
print("The datatype of series elements is:")
print(mySeries.dtype)

The input list is:
[1, 2, 3, 4]
The series is:
0    1
1    2
2    3
3    4
dtype: int64
The datatype of series elements is:
int64

import pandas as pd
names = [1,2,3.1,4.2]
print("The input list is:")
print(names)
print("The series is:")
mySeries=pd.Series(names)
print(mySeries)
print("The datatype of series elements is:")
print(mySeries.dtype)

The input list is:
[1, 2, 3.1, 4.2]
The series is:
0    1.0
1    2.0
2    3.1
3    4.2
dtype: float64
The datatype of series elements is:
float64

import pandas as pd
names = ['Aditya', 'Chris', 'Joel']
print("The input list is:")
print(names)
print("The series is:")
mySeries=pd.Series(names)
print(mySeries)
print("The datatype of series elements is:")
print(mySeries.dtype)

The input list is:
['Aditya', 'Chris', 'Joel']
The series is:
0    Aditya
1     Chris
2      Joel
dtype: object
The datatype of series elements is:
object

import pandas as pd
names = [1, 2.2, 'Joel']
print("The input list is:")
print(names)
print("The series is:")
mySeries=pd.Series(names)
print(mySeries)
print("The datatype of series elements is:")
print(mySeries.dtype)

The input list is:
[1, 2.2, 'Joel']
The series is:
0       1
1     2.2
2    Joel
dtype: object
The datatype of series elements is:
object

import pandas as pd
names = [1, 2.2, "Aditya", None]
print("The input list is:")
print(names)
print("The series is:")
mySeries=pd.Series(names)
print(mySeries)
print("The datatype of series elements is:")
print(mySeries.dtype)

The input list is:
[1, 2.2, 'Aditya', None]
The series is:
0         1
1       2.2
2    Aditya
3      None
dtype: object
The datatype of series elements is:
object

import pandas as pd
names = [1, 2.2, 3.2, None]
print("The input list is:")
print(names)
print("The series is:")
mySeries=pd.Series(names)
print(mySeries)
print("The datatype of series elements is:")
print(mySeries.dtype)

The input list is:
[1, 2.2, 3.2, None]
The series is:
0    1.0
1    2.2
2    3.2
3    NaN
dtype: float64
The datatype of series elements is:
float64

import pandas as pd
names = [1, 2.2, 3.2, None]
print("The input list is:")
print(names)
print("The series is:")
mySeries=pd.Series(names)
print(mySeries)
print("The datatype of series elements is:")
print(mySeries.dtype)

The input list is:
[1, 2.2, 'Aditya', None]
The series is:
0         1
1       2.2
2    Aditya
3      None
dtype: object
The datatype of series elements is:
object

import pandas as pd
names = [1, 2.2, "Aditya", None]
print("The input list is:")
print(names)
print("The series is:")
mySeries=pd.Series(names)
print(mySeries)
index=2
myVal=mySeries[index]
print("Element at index {} is {}".format(index,myVal))

The input list is:
[1, 2.2, 'Aditya', None]
The series is:
0         1
1       2.2
2    Aditya
3      None
dtype: object
Element at index 2 is Aditya

import pandas as pd
names = [1, 2.2, "Aditya", None]
print("The input list is:")
print(names)
print("The series is:")
mySeries=pd.Series(names, index=["A","B", "C", "D"])
print(mySeries)
index="B"
myVal=mySeries[index]
print("Element at index {} is {}".format(index,myVal))

The input list is:
[1, 2.2, 'Aditya', None]
The series is:
A         1
B       2.2
C    Aditya
D      None
dtype: object
Element at index B is 2.2

import pandas as pd
names = [1, 2.2, "Aditya", None]
print("The input list is:")
print(names)
print("The series is:")
mySeries=pd.Series(names, index=[4,5,6,7])
print(mySeries)
index=0
myVal=mySeries[index]
print("Element at index {} is {}".format(index,myVal))

The input list is:
[1, 2.2, 'Aditya', None]
The series is:
4         1
5       2.2
6    Aditya
7      None
dtype: object

---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
/tmp/ipykernel_6004/208185265.py in <module>
      7 print(mySeries)
      8 index=0
----> 9 myVal=mySeries[index]
     10 print("Element at index {} is {}".format(index,myVal))

KeyError: 0

import pandas as pd
names = [1, 2.2, "Aditya", None]
print("The input list is:")
print(names)
print("The series is:")
mySeries=pd.Series(names)
print(mySeries)
position=0
myVal=mySeries.iloc[position]
print("Element at position {} is {}".format(position,myVal))

The input list is:
[1, 2.2, 'Aditya', None]
The series is:
0         1
1       2.2
2    Aditya
3      None
dtype: object
Element at position 0 is 1

import pandas as pd
names = [1, 2.2, "Aditya", None]
print("The input list is:")
print(names)
print("The series is:")
mySeries=pd.Series(names,index=[1,2,3,4])
print(mySeries)
position=0
myVal=mySeries.iloc[position]
print("Element at position {} is {}".format(position,myVal))

The input list is:
[1, 2.2, 'Aditya', None]
The series is:
1         1
2       2.2
3    Aditya
4      None
dtype: object
Element at position 0 is 1

import pandas as pd
names = [1, 2.2, "Aditya", None]
print("The input list is:")
print(names)
print("The series is:")
mySeries=pd.Series(names,index=["A","B","C","D"])
print(mySeries)
index="A"
myVal=mySeries.loc[index]
print("Element at index {} is {}".format(index,myVal))

The input list is:
[1, 2.2, 'Aditya', None]
The series is:
A         1
B       2.2
C    Aditya
D      None
dtype: object
Element at index A is 1

import pandas as pd
names = [1, 2.2, "Aditya", None]
print("The input list is:")
print(names)
print("The series is:")
mySeries=pd.Series(names,index=["A","B","C","D"])
print(mySeries)
index="D"
mySeries.loc[index]=1117
print("The modified series is:")
print(mySeries)

The input list is:
[1, 2.2, 'Aditya', None]
The series is:
A         1
B       2.2
C    Aditya
D      None
dtype: object
The modified series is:
A         1
B       2.2
C    Aditya
D      1117
dtype: object 

import pandas as pd
names = [1, 2.2, "Aditya", None]
print("The input list is:")
print(names)
print("The series is:")
mySeries=pd.Series(names,index=["A","B","C","D"])
print(mySeries)
newSeries=pd.Series([1117])
mySeries=mySeries.append(newSeries)
print("The modified series is:")
print(mySeries)

The input list is:
[1, 2.2, 'Aditya', None]
The series is:
A         1
B       2.2
C    Aditya
D      None
dtype: object
The modified series is:
A         1
B       2.2
C    Aditya
D      None
0      1117
dtype: object

import pandas as pd
names = [1, 2.2, "Aditya", None]
print("The input list is:")
print(names)
print("The series is:")
mySeries=pd.Series(names,index=["A","B","C","D"])
print(mySeries)
newSeries=pd.Series([1117])
mySeries=mySeries.append(newSeries, ignore_index=True )
print("The modified series is:")
print(mySeries)

The input list is:
[1, 2.2, 'Aditya', None]
The series is:
A         1
B       2.2
C    Aditya
D      None
dtype: object
The modified series is:
0         1
1       2.2
2    Aditya
3      None
4      1117
dtype: object

import pandas as pd
names = [1, 2.2, "Aditya", None]
print("The input list is:")
print(names)
print("The series is:")
mySeries=pd.Series(names,index=["A","B","C","D"])
print(mySeries)
newSeries=pd.Series([1117],index=["P"])
mySeries=mySeries.append(newSeries)
print("The modified series is:")
print(mySeries)

The input list is:
[1, 2.2, 'Aditya', None]
The series is:
A         1
B       2.2
C    Aditya
D      None
dtype: object
The modified series is:
A         1
B       2.2
C    Aditya
D      None
P      1117
dtype: object

import pandas as pd
names = [1, 2.2, "Aditya", None]
print("The series is:")
mySeries=pd.Series(names,index=["A","B","C","D"])
print(mySeries)
mySeries=mySeries.drop("A")
print("The modified series is:")
print(mySeries)

The series is:
A         1
B       2.2
C    Aditya
D      None
dtype: object
The modified series is:
B       2.2
C    Aditya
D      None
dtype: object

import pandas as pd
names = [1, 2.2, "Aditya", None]
print("The series is:")
mySeries=pd.Series(names,index=["A","B","C","D"])
print(mySeries)
mySeries=mySeries.drop(["A","D"])
print("The modified series is:")
print(mySeries)

The series is:
A         1
B       2.2
C    Aditya
D      None
dtype: object
The modified series is:
B       2.2
C    Aditya
dtype: object 

import pandas as pd
names = [1, 2.2, "Aditya", None]
print("The series is:")
mySeries=pd.Series(names,index=["A","B","C","D"])
print(mySeries)
mySeries.drop(["A","D"], inplace=True)
print("The modified series is:")
print(mySeries)

The series is:
A         1
B       2.2
C    Aditya
D      None
dtype: object
The modified series is:
B       2.2
C    Aditya
dtype: object

import pandas as pd
names = [1, 2.2, "Aditya", None]
print("The series is:")
mySeries=pd.Series(names)
print(mySeries)
mySeries.drop(0, inplace=True)
print("The modified series is:")
print(mySeries)

The series is:
0         1
1       2.2
2    Aditya
3      None
dtype: object
The modified series is:
1       2.2
2    Aditya
3      None
dtype: object

import pandas as pd
names = [1, 2.2, "Aditya", None]
print("The series is:")
mySeries=pd.Series(names)
print(mySeries)
mySeries.drop([0,1], inplace=True)
print("The modified series is:")
print(mySeries)

The series is:
0         1
1       2.2
2    Aditya
3      None
dtype: object
The modified series is:
2    Aditya
3      None
dtype: object

import pandas as pd
names = [1, 2.2, "Aditya", None]
print("The series is:")
mySeries=pd.Series(names)
print(mySeries)
mySeries[0]=12345
print("The modified series is:")
print(mySeries)

The series is:
0         1
1       2.2
2    Aditya
3      None
dtype: object
The modified series is:
0     12345
1       2.2
2    Aditya
3      None
dtype: object

import pandas as pd
names = [1, 2.2, "Aditya", None]
print("The series is:")
mySeries=pd.Series(names,index=["A","B","C","D"])
print(mySeries)
mySeries["D"]="Chris"
print("The modified series is:")
print(mySeries)

The series is:
A         1
B       2.2
C    Aditya
D      None
dtype: object
The modified series is:
A         1
B       2.2
C    Aditya
D     Chris
dtype: object

import json
import urllib2 

url = "http://api.twitter.com/1/statuses/user_timeline.json?screen_name=wordpress" 

print data 

#Importing modules
import json
import urllib2

# Open the URL and the screen name
url = "http://api.twitter.com/1/statuses/user_timeline.json?screen_name=wordpress"

# This takes a python object and dumps it to a string which is a JSON representation of that object
data = json.load(urllib2.urlopen(url))

#print the result
print data 

 data = {
    a: 0,
    b: 9.6,
    c: "Hello World",
    d: {
        a: 4
    }
} 

 import json

data = {
    a: 0,
    b: 9.6,
    c: "Hello World",
    d: {
        a: 4
    }
}

json_data = json.dumps(data)
print(json_data) 

 {"c": "Hello World", "b": 9.6, "d": {"e": [89, 90]}, "a": 0} 

 import json

data = {
    a: 0,
    b: 9.6,
    c: "Hello World",
    d: {
        a: 4
    }
}

json_data = json.dumps(data, sort_keys=True)
print(json_data) 

 {"a": 0, "b": 9.6, "c": "Hello World", "d": {"e": [89, 90]}} 

import json

# Create a data structure
data = [ { 'Hola':'Hello', 'Hoi':"Hello", 'noun':"hello" } ]

print 'DATA:', (data)

DATA: [{'noun': 'hello', 'Hola': 'Hello', 'Hoi': 'Hello'}]

json_encoded = json.dumps(data)

# print to screen

print json_encoded

OUTPUT:

[{"noun": "hello", "Hola": "Hello", "Hoi": "Hello"}]

decoded_data = json.loads(json_encoded)

# print to screen

print decoded_data

OUTPUT:

[{u'noun': u'hello', u'Hola': u'Hello', u'Hoi': u'Hello’}]

 Syntax for creating a socket
sock = socket.socket (socket_family, socket_type)

Creates a stream socket
sock = socket.socket (socket.AF_INET, socket.SOCK_STREAM)

AF_INET 
Socket Family (here Address Family version 4 or IPv4) 

SOCK_STREAM Socket type TCP connections 

SOCK_DGRAM Socket type UDP connections 

Translate a host name to IPv4 address format 
gethostbyname("host") 

Translate a host name to IPv4 address format, extended interface
socket.gethostbyname_ex("host")  

Get the fqdn (fully qualified domain name)
socket.getfqdn("8.8.8.8")  

Returns the hostname of the machine..
socket.gethostname()  

Exception handling
socket.error

#!/usr/bin/env python
import socket
import subprocess
import sys
from datetime import datetime

# Clear the screen
subprocess.call('clear', shell=True)

# Ask for input
remoteServer    = raw_input("Enter a remote host to scan: ")
remoteServerIP  = socket.gethostbyname(remoteServer)

# Print a nice banner with information on which host we are about to scan
print "-" * 60
print "Please wait, scanning remote host", remoteServerIP
print "-" * 60

# Check what time the scan started
t1 = datetime.now()

# Using the range function to specify ports (here it will scans all ports between 1 and 1024)

# We also put in some error handling for catching errors

try:
    for port in range(1,1025):  
        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        result = sock.connect_ex((remoteServerIP, port))
        if result == 0:
            print "Port {}: 	 Open".format(port)
        sock.close()

except KeyboardInterrupt:
    print "You pressed Ctrl+C"
    sys.exit()

except socket.gaierror:
    print 'Hostname could not be resolved. Exiting'
    sys.exit()

except socket.error:
    print "Couldn't connect to server"
    sys.exit()

# Checking the time again
t2 = datetime.now()

# Calculates the difference of time, to see how long it took to run the script
total =  t2 - t1

# Printing the information to screen
print 'Scanning Completed in: ', total 

$ python portscanner.py

Enter a remote host to scan: www.your_host_example.com
------------------------------------------------------------
Please wait, scanning remote host xxxx.xxxx.xxxx.xxxx
------------------------------------------------------------

Port 21:   Open
Port 22:    Open
Port 23:    Open
Port 80:    Open
Port 110:   Open
Port 111:   Open
Port 143:   Open
Port 443:   Open
Port 465:   Open
Port 587:   Open
Port 993:   Open
Port 995:   Open

Scanning Completed in:  0:06:34.705170 

myStr="Python For Beginners"
print("The input string is:",myStr)
strLen=len(myStr)
range_obj=range(strLen)
character="F"
for index in range_obj:
    if myStr[index]==character:
        print("The character {} is at index {}".format(character,index))
        break

The input string is: Python For Beginners
The character F is at index 7

myStr="Python For Beginners"
print("The input string is:",myStr)
strLen=len(myStr)
range_obj=range(strLen)
character="n"
for index in range_obj:
    if myStr[index]==character:
        print("The character {} is at index {}".format(character,index))

The input string is: Python For Beginners
The character n is at index 5
The character n is at index 15
The character n is at index 16

myStr="Python For Beginners"
print("The input string is:",myStr)
strLen=len(myStr)
range_obj=range(strLen)
character="n"
position=-1
for index in range_obj:
    if myStr[index]==character:
        position=index
print("The character {} is at rightmost index {}".format(character,position))

The input string is: Python For Beginners
The character n is at rightmost index 16

myStr="Python For Beginners"
print("The input string is:",myStr)
strLen=len(myStr)
range_obj=range(strLen)
character="n"
for index in range_obj:
    if myStr[strLen-index-1]==character:
        print("The character {} is at position {} from right.".format(character,index+1))
        break

The input string is: Python For Beginners
The character n is at position 4 from right.

myStr="Python For Beginners"
print("The input string is:",myStr)
strLen=len(myStr)
character="n"
position=-1
while position<strLen-1:
    if myStr[position+1]==character:
        print("The character {} is at position {}.".format(character,position+1))
        break
    position+=1

The input string is: Python For Beginners
The character n is at position 5.

myStr="Python For Beginners"
print("The input string is:",myStr)
strLen=len(myStr)
character="n"
position=-1
while position<strLen-1:
    if myStr[position+1]==character:
        print("The character {} is at position {}.".format(character,position+1))
    position+=1

The input string is: Python For Beginners
The character n is at position 5.
The character n is at position 15.
The character n is at position 16.

myStr="Python For Beginners"
print("The input string is:",myStr)
strLen=len(myStr)
character="n"
position=-1
rposition=0
while position<strLen-1:
    if myStr[position+1]==character:
        rposition=position+1
    position+=1
print("The character {} is at rightmost position {}.".format(character,rposition))

The input string is: Python For Beginners
The character n is at rightmost position 16.

myStr="Python For Beginners"
print("The input string is:",myStr)
strLen=len(myStr)
character="n"
position=0
while position<strLen-1:
    if myStr[strLen-position-1]==character:
        print("The character {} is at position {} from right.".format(character,position+1))
        break
    position+=1

The input string is: Python For Beginners
The character n is at position 4 from right.

myStr="Python For Beginners"
print("The input string is:",myStr)
strLen=len(myStr)
character="n"
position=myStr.find(character)
print("The character {} is at position {}.".format(character,position))

The input string is: Python For Beginners
The character n is at position 5.

myStr="Python For Beginners"
print("The input string is:",myStr)
strLen=len(myStr)
character="n"
position=myStr.index(character)
print("The character {} is at index {}.".format(character,position))

The input string is: Python For Beginners
The character n is at index 5.

myStr="Python For Beginners"
print("The input string is:",myStr)
strLen=len(myStr)
character="n"
position=myStr.rfind(character)
print("The character {} is at rightmost position {} .".format(character,position))

The input string is: Python For Beginners
The character n is at rightmost position 16 .

class BinaryTreeNode:
    def __init__(self, data):
        self.data = data
        self.leftChild = None
        self.rightChild = None

def postorder(root):
    # if root is None,return
    if root is None:
        return
    # traverse left subtree
    postorder(root.leftChild)

    # traverse right subtree
    postorder(root.rightChild)
    # print the current node
    print(root.data, end=" ,")

def insert(root, newValue):
    # if binary search tree is empty, create a new node and declare it as root
    if root is None:
        root = BinaryTreeNode(newValue)
        return root
    # if newValue is less than value of data in root, add it to left subtree and proceed recursively
    if newValue < root.data:
        root.leftChild = insert(root.leftChild, newValue)
    else:
        # if newValue is greater than value of data in root, add it to right subtree and proceed recursively
        root.rightChild = insert(root.rightChild, newValue)
    return root

root = insert(None, 50)
insert(root, 20)
insert(root, 53)
insert(root, 11)
insert(root, 22)
insert(root, 52)
insert(root, 78)
print("Postorder traversal of the binary tree is:")
postorder(root) 

Postorder traversal of the binary tree is:
11 ,22 ,20 ,52 ,78 ,53 ,50 ,

class BinaryTreeNode:
    def __init__(self, data):
        self.data = data
        self.leftChild = None
        self.rightChild = None

def preorder(root):
    # if root is None,return
    if root is None:
        return
    # print the current node
    print(root.data, end=" ,")
    # traverse left subtree
    preorder(root.leftChild)

    # traverse right subtree
    preorder(root.rightChild)

def insert(root, newValue):
    # if binary search tree is empty, create a new node and declare it as root
    if root is None:
        root = BinaryTreeNode(newValue)
        return root
    # if newValue is less than value of data in root, add it to left subtree and proceed recursively
    if newValue < root.data:
        root.leftChild = insert(root.leftChild, newValue)
    else:
        # if newValue is greater than value of data in root, add it to right subtree and proceed recursively
        root.rightChild = insert(root.rightChild, newValue)
    return root

root = insert(None, 50)
insert(root, 20)
insert(root, 53)
insert(root, 11)
insert(root, 22)
insert(root, 52)
insert(root, 78)
print("Preorder traversal of the binary tree is:")
preorder(root) 

Preorder traversal of the binary tree is:
50 ,20 ,11 ,22 ,53 ,52 ,78 ,

print("This is the first line.")
print("This is the second line.")
print("This is the third line.")
print("This is the fourth line.")

This is the first line.
This is the second line.
This is the third line.
This is the fourth line.

print("This is the first line.", end=".")
print("This is the second line.", end=".")
print("This is the third line.", end=".")
print("This is the fourth line.", end=".")

This is the first line..This is the second line..This is the third line..This is the fourth line..

print("This is the first line.", end=",")
print("This is the second line.", end=",")
print("This is the third line.", end=",")
print("This is the fourth line.", end=",")

This is the first line.,This is the second line.,This is the third line.,This is the fourth line.,

myList1 = [1, 2, 3, 4]
myList2 = [1, True, False]
myList3 = []
print("The list is:", myList1)
output = all(myList1)
print("All the elements of the list evaluate to True:", output)
print("The list is:", myList2)
output = all(myList2)
print("All the elements of the list evaluate to True:", output)
print("The list is:", myList3)
output = all(myList3)
print("All the elements of the list evaluate to True:", output)

The list is: [1, 2, 3, 4]
All the [elements of the list](https://www.pythonforbeginners.com/basics/find-the-index-of-an-element-in-a-list) evaluate to True: True
The list is: [1, True, False]
All the elements of the list evaluate to True: False
The list is: []
All the [elements of the list](https://www.pythonforbeginners.com/basics/find-the-index-of-an-element-in-a-list) evaluate to True: True

myList1 = [1, 2, 3, 4]
myList2 = [1, True, False]
myList3 = []
print("The list is:", myList1)
output = all(myList1)
print("All the elements of the list evaluate to True:", output)
print("The list is:", myList2)
output = all(myList2)
print("All the elements of the list evaluate to True:", output)
print("The list is:", myList3)
output = all(myList3)
print("All the elements of the list evaluate to True:", output)

The list is: [1, 2, 3, 4]
All the elements of the list evaluate to True: True
The list is: [1, True, False]
All the elements of the list evaluate to True: False
The list is: []
All the elements of the list evaluate to True: True

myStr1 = "PythonForBeginners"
myStr2 = ""
print("The string is:", myStr1)
output = all(myStr1)
print("The output is:", output)
print("The string is:", myStr2)
output = all(myStr2)
print("The output is:", output)

The string is: PythonForBeginners
The output is: True
The string is: 
The output is: True

mySet1 = {1, 2, 3, 4}
mySet2 = {1, 2, True, False}
mySet3 = set()
print("The Set is:", mySet1)
output = all(mySet1)
print("All the elements of the set evaluate to True:", output)
print("The Set is:", mySet2)
output = all(mySet2)
print("All the elements of the set evaluate to True:", output)
print("The Set is:", mySet3)
output = all(mySet3)
print("All the elements of the set evaluate to True:", output)

The Set is: {1, 2, 3, 4}
All the elements of the set evaluate to True: True
The Set is: {False, 1, 2}
All the elements of the set evaluate to True: False
The Set is: set()
All the elements of the set evaluate to True: True

myDict1 = {1: 1, 2: 2, 3: 3, True: 4}
myDict2 = {False: 1, 1: 2, True: False}
myDict3 = {}
print("The Dictionary is:", myDict1)
output = all(myDict1)
print("All the keys of the dictionary evaluate to True:", output)
print("The Dictionary is:", myDict2)
output = all(myDict2)
print("All the keys of the dictionary evaluate to True:", output)
print("The Dictionary is:", myDict3)
output = all(myDict3)
print("All the keys of the dictionary evaluate to True:", output)

The Dictionary is: {1: 4, 2: 2, 3: 3}
All the keys of the dictionary evaluate to True: True
The Dictionary is: {False: 1, 1: False}
All the keys of the dictionary evaluate to True: False
The Dictionary is: {}
All the keys of the dictionary evaluate to True: True

# Make the connection
connection = MySQLdb.connect(host='localhost',user='alex',passwd='secret',db='myDB')
cursor = connection.cursor()

# Lists the tables in demo
sql = "SHOW TABLES;"

# Execute the SQL query and get the response
cursor.execute(sql)
response = cursor.fetchall()

# Loop through the response and print table names
for row in response:
    print row[0] 

myList1 = [1, 2, 3, 4]
myList2 = [False, False, False]
myList3 = []
print("The list is:", myList1)
output = any(myList1)
print("List contains one or more  elements that evaluate to True:", output)
print("The list is:", myList2)
output = any(myList2)
print("List contains one or more  elements that evaluate to True:", output)
print("The list is:", myList3)
output = any(myList3)
print("List contains one or more  elements that evaluate to True:", output)

The list is: [1, 2, 3, 4]
List contains one or more  elements that evaluate to True: True
The list is: [False, False, False]
List contains one or more  elements that evaluate to True: False
The list is: []
List contains one or more  elements that evaluate to True: False

myList1 = [1, 2, 3, 4]
myList2 = [False, False, False]
myList3 = []
print("The list is:", myList1)
output = any(myList1)
print("List contains one or more  elements that evaluate to True:", output)
print("The list is:", myList2)
output = any(myList2)
print("List contains one or more  elements that evaluate to True:", output)
print("The list is:", myList3)
output = any(myList3)
print("List contains one or more  elements that evaluate to True:", output)

The list is: [1, 2, 3, 4]
List contains one or more  elements that evaluate to True: True
The list is: [False, False, False]
List contains one or more  elements that evaluate to True: False
The list is: []
List contains one or more  elements that evaluate to True: False

myStr1="PythonForBeginners"
myStr2=""
print("The string is:", myStr1)
output = any(myStr1)
print("The string contains one or more  elements:", output)
print("The string is:", myStr2)
output = any(myStr2)
print("The string contains one or more  elements:", output)

The string is: PythonForBeginners
The string contains one or more  elements: True
The string is: 
The string contains one or more  elements: False 

mySet1 = {1, 2, 3, 4}
mySet2 = {False}
mySet3 = set()
print("The Set is:", mySet1)
output = any(mySet1)
print("Set contains one or more  elements that evaluate to True:", output)
print("The Set is:", mySet2)
output = any(mySet2)
print("Set contains one or more  elements that evaluate to True:", output)
print("The Set is:", mySet3)
output = any(mySet3)
print("Set contains one or more  elements that evaluate to True:", output)

The Set is: {1, 2, 3, 4}
Set contains one or more  elements that evaluate to True: True
The Set is: {False}
Set contains one or more  elements that evaluate to True: False
The Set is: set()
Set contains one or more  elements that evaluate to True: False

myDict1 = {1: 1, 2: 2, 3: 3, 4: 4}
myDict2 = {False: 1}
myDict3 = {}
print("The Dictionary is:", myDict1)
output = any(myDict1)
print("Dictionary contains one or more  keys that evaluate to True:", output)
print("The Dictionary is:", myDict2)
output = any(myDict2)
print("Dictionary contains one or more  keys that evaluate to True:", output)
print("The Dictionary is:", myDict3)
output = any(myDict3)
print("Dictionary contains one or more  keys that evaluate to True:", output)

The Dictionary is: {1: 1, 2: 2, 3: 3, 4: 4}
Dictionary contains one or more  keys that evaluate to True: True
The Dictionary is: {False: 1}
Dictionary contains one or more  keys that evaluate to True: False
The Dictionary is: {}
Dictionary contains one or more  keys that evaluate to True: False

import json
import urllib2

# open the url and the screen name 
# (The screen name is the screen name of the user for whom to return results for)
url = "http://api.twitter.com/1/statuses/user_timeline.json?screen_name=python"

# this takes a python object and dumps it to a string which is a JSON
# representation of that object
data = json.load(urllib2.urlopen(url))

# print the result
print data

 BeautifulSoup is a Python library from [www.crummy.com](http://www.crummy.com/software/BeautifulSoup/ "crummy") 

 On their website they write "Beautiful Soup parses anything you give it, and does the tree traversal stuff for you. 

**You can tell it to:**

"Find all the links"

"Find all the links of class externalLink"

"Find all the links whose urls match "foo.com"

"Find the table heading that's got bold text, then give me that text."" 

 In this example, we will try and find a link (a tag) in a webpage. 

Before we start, we have to import two modules. (BeutifulSoup and urllib2). 

Urlib2 is used to open the URL we want. 

We will use the soup.findAll method to search through the soup object to match fortext and html tags within the page. 

from BeautifulSoup import BeautifulSoup
import urllib2

url = urllib2.urlopen("http://www.python.org")
content = url.read()
soup = BeautifulSoup(content)
links = soup.findAll("a")

 That will print out all the elements in python.org with an "a" tag. 

(The "a" tag defines a hyperlink, which is used to link from one page to another.) 

 To make it a bit more useful, we can specify the URL's we want to return. 

from BeautifulSoup import BeautifulSoup
import urllib2
import re

url = urllib2.urlopen("http://www.python.org")
content = url.read()
soup = BeautifulSoup(content)
for a in soup.findAll('a',href=True):
    if re.findall('python', a['href']):
        print "Found the URL:", a['href']

 I recommend that you head over to [http://www.crummy.com](http://www.crummy.com/software/BeautifulSoup/ "Crummy") to read more about what you can do with this awesome module. 

#import the library used to query a website
import urllib2

#specify the url you want to query
url = "http://www.python.org"

#Query the website and return the html to the variable 'page'
page = urllib2.urlopen(url)

#import the Beautiful soup functions to parse the data returned from the website
from BeautifulSoup import BeautifulSoup

#Parse the html in the 'page' variable, and store it in Beautiful Soup format
soup = BeautifulSoup(page)

#to print the soup.head is the head tag and soup.head.title is the title tag
print soup.head
print soup.head.title

#to print the length of the page, use the len function
print len(page)

#create a new variable to store the data you want to find.
tags = soup.findAll('a')

#to print all the links
print tags

#to get all titles and print the contents of each title
titles = soup.findAll('span', attrs = { 'class' : 'titletext' })
for title in allTitles:
    print title.contents 

myNum1 = 8
binNum1 = bin(myNum1)
myNum2 = 14
binNum2 = bin(myNum2)
print("Binary of {} is {}.".format(myNum1, binNum1))
print("Binary of {} is  {}.".format(myNum2, binNum2))

Binary of 8 is 0b1000.
Binary of 14 is  0b1110. 

myNum1 = 8
myNum2 = 14
andNum = myNum1 & myNum2
print("Operand 1 is:", myNum1)
print("operand 2 is:", myNum2)
print("Result of the AND operation on {} and {} is {}.".format(myNum1, myNum2, andNum))

Operand 1 is: 8
operand 2 is: 14
Result of the AND operation on 8 and 14 is 8.

myNum1 = 8
myNum2 = 14
orNum = myNum1 | myNum2
print("Operand 1 is:", myNum1)
print("operand 2 is:", myNum2)
print("Result of the OR operation on {} and {} is {}.".format(myNum1, myNum2, orNum)) 

Operand 1 is: 8
operand 2 is: 14
Result of the OR operation on 8 and 14 is 14.

myNum1 = 14
notNum = ~myNum1
print("Operand 1 is:", myNum1)
print("Result of the NOT operation on {} is {}.".format(myNum1, notNum))

Operand 1 is: 14
Result of the NOT operation on 14 is -15.

myNum1 = 8
myNum2 = 14
xorNum = myNum1 ^ myNum2
print("Operand 1 is:", myNum1)
print("operand 2 is:", myNum2)
print("Result of the XOR operation on {} and {} is {}.".format(myNum1, myNum2, xorNum))

Operand 1 is: 8
operand 2 is: 14
Result of the XOR operation on 8 and 14 is 6.

#!/usr/bin/env python
Fahrenheit = int(raw_input("Enter a temperature in Fahrenheit: "))

Celsius = (Fahrenheit - 32) * 5.0/9.0

print "Temperature:", Fahrenheit, "Fahrenheit = ", Celsius, " C" 

 #!/usr/bin/env python
Celsius = int(raw_input("Enter a temperature in Celsius: "))

Fahrenheit = 9.0/5.0 * Celsius + 32

print "Temperature:", Celsius, "Celsius = ", Fahrenheit, " F" 

 This script converts speed from KM/H to MPH, which may be handy for calculating
speed limits when driving abroad, especially for UK and US drivers. 

The conversion formula for kph to mph is : 1 kilometre = 0.621371192 miles 

#!/usr/bin/env python
kmh = int(raw_input("Enter km/h: "))
mph =  0.6214 * kmh
print "Speed:", kmh, "KM/H = ", mph, "MPH"

import collections 

from collections import Counter 

import collections

print collections.Counter(['a', 'b', 'c', 'a', 'b', 'b'])

print collections.Counter({'a':2, 'b':3, 'c':1})

print collections.Counter(a=2, b=3, c=1) 

$ python collections_counter_init.py

Counter({'b': 3, 'a': 2, 'c': 1})
Counter({'b': 3, 'a': 2, 'c': 1})
Counter({'b': 3, 'a': 2, 'c': 1}) 

import collections

c = collections.Counter()
print 'Initial :', c

c.update('abcdaab')
print 'Sequence:', c

c.update({'a':1, 'd':5})
print 'Dict    :', c 

$ python collections_counter_update.py

Initial : Counter()

Sequence: Counter({'a': 3, 'b': 2, 'c': 1, 'd': 1})

Dict    : Counter({'d': 6, 'a': 4, 'b': 2, 'c': 1}) 

import collections

c = collections.Counter('abcdaab')

for letter in 'abcde':
    print '%s : %d' % (letter, c[letter]) 

$ python collections_counter_get_values.py

a : 3
b : 2
c : 1
d : 1
e : 0 

import collections

c = collections.Counter('extremely')

c['z'] = 0

print c

print list(c.elements()) 

$ python collections_counter_elements.py

Counter({'e': 3, 'm': 1, 'l': 1, 'r': 1, 't': 1, 'y': 1, 'x': 1, 'z': 0})
['e', 'e', 'e', 'm', 'l', 'r', 't', 'y', 'x'] 

import collections

c = collections.Counter()
with open('/usr/share/dict/words', 'rt') as f:
    for line in f:
        c.update(line.rstrip().lower())

print 'Most common:'
for letter, count in c.most_common(3):
    print '%s: %7d' % (letter, count) 

$ python collections_counter_most_common.py

Most common:
e:  234803
i:  200613
a:  198938 

import collections

c1 = collections.Counter(['a', 'b', 'c', 'a', 'b', 'b'])
c2 = collections.Counter('alphabet')

print 'C1:', c1
print 'C2:', c2

print '
Combined counts:'
print c1 + c2

print '
Subtraction:'
print c1 - c2

print '
Intersection (taking positive minimums):'
print c1 & c2

print '
Union (taking maximums):'
print c1 | c2 

$ python collections_counter_arithmetic.py

C1: Counter({'b': 3, 'a': 2, 'c': 1})
C2: Counter({'a': 2, 'b': 1, 'e': 1, 'h': 1, 'l': 1, 'p': 1, 't': 1})

#Combined counts:
Counter({'a': 4, 'b': 4, 'c': 1, 'e': 1, 'h': 1, 'l': 1, 'p': 1, 't': 1})

#Subtraction:
Counter({'b': 2, 'c': 1})

#Intersection (taking positive minimums):
Counter({'a': 2, 'b': 1})

#Union (taking maximums):
Counter({'b': 3, 'a': 2, 'c': 1, 'e': 1, 'h': 1, 'l': 1, 'p': 1, 't': 1}) 

cnt = Counter()

for word in ['red', 'blue', 'red', 'green', 'blue', 'blue']:
    cnt[word] += 1

print cnt

Counter({'blue': 3, 'red': 2, 'green': 1}) 

mywords = ['red', 'blue', 'red', 'green', 'blue', 'blue']

cnt = Counter(mywords)

print cnt

Counter({'blue': 3, 'red': 2, 'green': 1}) 

import re

words = re.findall('w+', open('hamlet.txt').read().lower())

print Counter(words).most_common(10)

[('the', 1143), ('and', 966), ('to', 762), ('of', 669), ('i', 631),
 ('you', 554),  ('a', 546), ('my', 514), ('hamlet', 471), ('in', 451)] 

myNum1 = 14
myNum2 = 14
myNum3 = 10
myNum4 = 5
compare12 = myNum1 == myNum2
compare13 = myNum1 == myNum3
compare14 = myNum1 == myNum4
print("{} is equal to {}?: {}".format(myNum1, myNum2, compare12))
print("{} is equal to {}?: {}".format(myNum1, myNum3, compare13))
print("{} is equal to {}?: {}".format(myNum1, myNum4, compare14))

14 is equal to 14?: True
14 is equal to 10?: False
14 is equal to 5?: False

myNum1 = 14
myNum2 = 14
myNum3 = 10
myNum4 = 5
compare12 = myNum1 != myNum2
compare13 = myNum1 != myNum3
compare14 = myNum1 != myNum4
print("{} is not equal to {}?: {}".format(myNum1, myNum2, compare12))
print("{} is not equal to {}?: {}".format(myNum1, myNum3, compare13))
print("{} is not equal to {}?: {}".format(myNum1, myNum4, compare14))

14 is not equal to 14?: False
14 is not equal to 10?: True
14 is not equal to 5?: True

myNum1 = 14
myNum2 = 14
myNum3 = 10
myNum4 = 5
compare12 = myNum1 < myNum2
compare13 = myNum3 < myNum1
compare14 = myNum1 < myNum4
print("{} is less than {}?: {}".format(myNum1, myNum2, compare12))
print("{} is less than {}?: {}".format(myNum3, myNum1, compare13))
print("{} is less than {}?: {}".format(myNum1, myNum4, compare14))

14 is less than 14?: False
10 is less than 14?: True
14 is less than 5?: False

myNum1 = 14
myNum2 = 14
myNum3 = 10
myNum4 = 5
compare12 = myNum1 > myNum2
compare13 = myNum1 > myNum3
compare14 = myNum1 > myNum4
print("{} is greater than {}?: {}".format(myNum1, myNum2, compare12))
print("{} is greater than {}?: {}".format(myNum1, myNum3, compare13))
print("{} is greater than {}?: {}".format(myNum1, myNum4, compare14))

14 is greater than 14?: False
14 is greater than 10?: True
14 is greater than 5?: True

myNum1 = 14
myNum2 = 14
myNum3 = 10
myNum4 = 5
compare12 = myNum1 <= myNum2
compare13 = myNum3 <= myNum1
compare14 = myNum1 <= myNum4
print("{} is less than or equal to {}?: {}".format(myNum1, myNum2, compare12))
print("{} is less than or equal to {}?: {}".format(myNum3, myNum1, compare13))
print("{} is less than or equal to {}?: {}".format(myNum1, myNum4, compare14)) 

14 is less than or equal to 14?: True
10 is less than or equal to 14?: True
14 is less than or equal to 5?: False

myNum1 = 14
myNum2 = 14
myNum3 = 10
myNum4 = 5
compare12 = myNum1 >= myNum2
compare13 = myNum1 >= myNum3
compare14 = myNum1 >= myNum4
print("{} is greater than or equal to {}?: {}".format(myNum1, myNum2, compare12))
print("{} is greater than or equal to {}?: {}".format(myNum1, myNum3, compare13))
print("{} is greater than or equal to {}?: {}".format(myNum1, myNum4, compare14)) 

14 is greater than or equal to 14?: True
14 is greater than or equal to 10?: True
14 is greater than or equal to 5?: True

if expression1:
   statement(s)
elif expression2:
   statement(s)
elif expression3:
   statement(s)
else:
   statement(s) 

if expression:
   statement(s)
else:
   statement(s) 

# This program compares two strings.

# Get a password from the user.
password = raw_input('Enter the password: ')

# Determine whether the correct password
# was entered.

if password == 'hello':
    print'Password Accepted'

else:
    print'Sorry, that is the wrong password.' 

#!/usr/bin/python

number = 20

guess = int(input('Enter an integer : '))

if guess == number:
    print('Congratulations, you guessed it.')

elif guess < number:
    print('No, it is a little higher than that')

else:
    print('No, it is a little lower than that') 

import time
import datetime

print "Time in seconds since the epoch: %s" %time.time()
print "Current date and time: " , datetime.datetime.now()
print "Or like this: " ,datetime.datetime.now().strftime("%y-%m-%d-%H-%M")

print "Current year: ", datetime.date.today().strftime("%Y")
print "Month of year: ", datetime.date.today().strftime("%B")
print "Week number of the year: ", datetime.date.today().strftime("%W")
print "Weekday of the week: ", datetime.date.today().strftime("%w")
print "Day of year: ", datetime.date.today().strftime("%j")
print "Day of the month : ", datetime.date.today().strftime("%d")
print "Day of week: ", datetime.date.today().strftime("%A") 

 Time in seconds since the epoch: 	1349271346.46
Current date and time:  		2012-10-03 15:35:46.461491
Or like this: 				12-10-03-15-35
Current year:  				2012
Month of year:  			October
Week number of the year:  		40
Weekday of the week:  			3
Day of year:  				277
Day of the month :  			03
Day of week:  				Wednesday 

 import datetime

mydate = datetime.date(1943,3, 13)  #year, month, day
print(mydate.strftime("%A")) 

 import datetime
now = datetime.datetime.now()
print "-" * 25
print now
print now.year
print now.month
print now.day
print now.hour
print now.minute
print now.second

print "-" * 25
print "1 week ago was it: ", now - datetime.timedelta(weeks=1)
print "100 days ago was: ", now - datetime.timedelta(days=100)
print "1 week from now is it: ",  now + datetime.timedelta(weeks=1)
print "In 1000 days from now is it: ", now + datetime.timedelta(days=1000)

print "-" * 25
birthday = datetime.datetime(2012,11,04)

print "Birthday in ... ", birthday - now
print "-" * 25

-------------------------
2012-10-03 16:04:56.703758
2012
10
3
16
4
56
-------------------------
The date and time one week ago from now was:  2012-09-26 16:04:56.703758
100 days ago was:  2012-06-25 16:04:56.703758
One week from now is it:  2012-10-10 16:04:56.703758
In 1000 days from now is it:  2015-06-30 16:04:56.703758
-------------------------
Birthday in ...  31 days, 7:55:03.296242
-------------------------

import random

def add(num1, num2):
   value = num1 + num2
   print("In the add() function. The sum of {} and {} is {}.".format(num1, num2, value))

def random_adder(func):
   val1 = random.randint(0, 10)
   val2 = random.randint(0, 100)
   print("In the random_adder. Values generated are {} and {}".format(val1, val2))
   func(val1, val2)

# execute
random_adder(add) 

In the random_adder. Values generated are 1 and 14
In the add() function. The sum of 1 and 14 is 15. 

*`import random

def add(num1, num2):
   value = num1 + num2
   print("In the add() function. The sum of {} and {} is {}.".format(num1, num2, value))

def random_adder(func):
   print("In the random_adder.")

   def operate():
       val1 = random.randint(0, 10)
       val2 = random.randint(0, 100)
       print("In the operate() function. Values generated are {} and {}".format(val1, val2))
       func(val1, val2)

   print("Returning the operate() function.")
   return operate

# execute
do_something = random_adder(add)
do_something()`* 

*`In the random_adder.
Returning the operate() function.
In the operate() function. Values generated are 3 and 25
In the add() function. The sum of 3 and 25 is 28.`* 

**`def add(num1, num2):
   value = num1 + num2
   print("In the add() function. The sum of {} and {} is {}.".format(num1, num2, value))

   def square():
       print("I am in square(). THe square of {} is {}.".format(value, value ** 2))

   print("calling square() function inside add().")
   square()

# execute
add(10, 20)`**

**`In the add() function. The sum of 10 and 20 is 30.
calling square() function inside add().
I am in square(). THe square of 30 is 900.`** 

**`def add(num1, num2):
   value = num1 + num2
   print("In the add() function. The sum of {} and {} is {}.".format(num1, num2, value))

   def square():
       print("I am in square(). THe square of {} is {}.".format(value, value ** 2))

   print("returning square() function.")
   return square

# execute
do_something = add(10, 20)
print("In the outer scope. Calling do_something.")
do_something()`** 

**`In the add() function. The sum of 10 and 20 is 30.
returning square() function.
In the outer scope. Calling do_something.
I am in square(). THe square of 30 is 900.`** 

**`def add(num1, num2):
   value = num1 + num2
   print("The sum of {} and {} is {}.".format(num1, num2, value))

# execute
add(10, 20)`** 

**`The sum of 10 and 20 is 30.`**

**`def decorator_function(func):
   def inner_function(*args):
       product = args[0] * args[1]
       print("Product of {} and {} is {} ".format(args[0], args[1], product))
       func(args[0], args[1])

   return inner_function`** 

**`def add(num1, num2):
   value = num1 + num2
   print("The sum of {} and {} is {}.".format(num1, num2, value))

def decorator_function(func):
   def inner_function(*args):
       product = args[0] * args[1]
       print("Product of {} and {} is {} ".format(args[0], args[1], product))
       func(args[0], args[1])

   return inner_function

# execute
do_something = decorator_function(add)
do_something(10, 20)`**

**`Product of 10 and 20 is 200
The sum of 10 and 20 is 30.`** 

**`def decorator_function(func):
   def inner_function(*args):
       product = args[0] * args[1]
       print("Product of {} and {} is {} ".format(args[0], args[1], product))
       return func(args[0], args[1])
   return inner_function

@decorator_function
def add(num1, num2):
   value = num1 + num2
   print("The sum of {} and {} is {}.".format(num1, num2, value))

# execute
add(10, 20)`**

**`Product of 10 and 20 is 200
The sum of 10 and 20 is 30.`** 

 A dictionary maps a set of key to a set of values. 

Dictionaries in Python are also known as hash tables. 

It requires that the keys are unique (within one dictionary), while the values maynot. 

The values of a dictionary can be of any type, but the keys must be of an
immutable data type such as strings, numbers, or tuples.

Dictionaries are like lists mutable

A dictionary is created with a pair of braces {}. 

For example, dic = {} creates an empty dictionary. 

Each key is separated from its value by a colon (:)

Placing a comma-separated list of key:value pairs within the braces adds initial
key:value pairs to the dictionary; this is also the way dictionaries are written 
on output. 

The main operations on a dictionary are storing a value with some key and
extracting the value given the key.

If you store using a key that is already in use, the old value associated with
that key is forgotten. 

 # key/value pairs declaration
 dict = {
 ‘key1′:’value1′,
 ‘key2′:’value2′,
 ‘key3′:’value3′
 }

#Get all keys
 dict.keys()

#Get all values
 dict.values()

#Modifying
 dict['key2'] = ‘value8′

#Accessing
 print dict['key1']

# prints ‘value2′
 print dict['key2']

# empty declaration + assignment of key-value pair
 emptyDict = {}
 emptyDict['key4']=’value4′

# looping through dictionaries (keys and values)
 for key in dict:
 print dict[key]

# sorting keys and accessing their value in order
 keys = dict.keys()
 keys.sort()
 for key in keys:
 print dict[key]

# looping their values directory (not in order)
 for value in dict.values():
 print value

# getting both the keys and values at once
 for key,value in dict.items():
 print “%s=%s” % (key,value)

# deleting an entry
 del dict['key2']

# delete all entries in a dictionary
 dict.clear()

# size of the dictionary
 len(dict) 

def my_function():
    """Do nothing, but document it.

    No, really, it doesn't do anything.
    """
    pass 

>>> print my_function.__doc__
Do nothing, but document it.

    No, really, it doesn't do anything. 

"""
Assuming this is file mymodule.py, then this string, being the
first statement in the file, will become the "mymodule" module's
docstring when the file is imported.
"""

class MyClass(object):
    """The class's docstring"""

    def my_method(self):
        """The method's docstring"""

def my_function():
    """The function's docstring""" 

>>> import mymodule
>>> help(mymodule) 

>>> help(mymodule.MyClass)
The class's docstring

>>> help(mymodule.MyClass.my_method)
The method's docstring

>>> help(mymodule.my_function)
The function's docstring 

 This post will be the first in a series of "Python Packing Manager" posts.

To know which one you are going to use, can be hard, as there are a few
different ones to choose from.

Let's start out with Easy_Install. 

 Distributes Python programs and libraries (based on the Python Eggs wrapper)

It's a python module (easy_install) that is bundled with setuptools.

It lets you automatically download, build, install, and manage Python packages.

Easy_Install looks in the Python Package Index (PyPI) for the desired packages
and uses the metadata there to download and install the package and its
dependencies. 

It is also hosted itself on the PyPI. 

 A Python egg is a way of distributing Python packages. 

"Eggs are to Pythons as Jars are to Java..."

For a great introduction about this, I suggest you head over to [this](http://mrtopf.de/blog/en/a-small-introduction-to-python-eggs/ "python_eggs") post 

 setuptools is a collection of enhancements to the Python distutils that allow
you to more easily build and distribute Python packages, especially ones that
have dependencies on other packages. 

 For basic use of easy_install, you need only supply the filename or URL of a 
source distribution or .egg file (Python Egg). 

By default, packages are installed to the running Python installation's
site-packages directory. 

 Install a package by name, searching PyPI for the latest version, 
and automatically downloading, building, and installing it:
**>>easy_install SQLObject**

Install or upgrade a package by name and version by finding links on
a given "download page":
**>>easy_install -f http://pythonpaste.org/package_index.html SQLObject**

Download a source distribution from a specified URL, automatically
building and installing it:
**>>easy_install http://example.com/path/to/MyPackage-1.2.3.tgz**

Install an already-downloaded .egg file:
**>>easy_install /my_downloads/OtherPackage-3.2.1-py2.3.egg**

Upgrade an already-installed package to the latest version listed on
PyPI:
**>>easy_install --upgrade PyProtocols**

Install a source distribution that's already downloaded and extracted
in the current directory (New in 0.5a9):
**>>easy_install .** 

 You don't need to do anything special to upgrade a package

Just install the new version, either by requesting a specific version, e.g.:
**>>easy_install "SomePackage==2.0"** 

 If you're installing to a directory on PYTHONPATH, or a configured "site"
directory (and not using -m), installing a package automatically replaces
any previous version in the easy-install.pth file, so that Python will
import the most-recently installed version by default. 

So, again, installing the newer version is the only upgrade step needed. 

 A version greater than the one you have now:
**>>easy_install "SomePackage>2.0"**

Using the upgrade flag, to find the latest available version on PyPI:
**>>easy_install --upgrade SomePackage**

Or by using a download page, direct download URL, or package filename:
**>>easy_install -f http://example.com/downloads ExamplePackage
>>easy_install 	  http://example.com/downloads/ExamplePackage-2.0-py2.4.egg
>>easy_install my_downloads/ExamplePackage-2.0.tgz** 

 If you've upgraded a package, but need to revert to a previously-installed
version, you can do so like this: 

 **>>easy_install PackageName==1.2.3** 
(where 1.2.3 is replaced by the exact version number you wish to switch to. 

If a package matching the requested name and version is not already installed in
a directory on sys.path, it will be located via PyPI and installed.)

To switch to the latest installed version of PackageName:
**>>easy_install PackageName**

This will activate the latest installed version! 

 If you have replaced a package with another version, then you can just delete
the package(s) you don't need by deleting the PackageName-versioninfo.egg file
or directory (found in the installation directory). 

 If you want to delete the currently installed version of a package 
(or all versions of a package), you should first run:
**>>easy_install -mxN PackageName**

This will ensure that Python doesn't continue to search for a package you're 
planning to remove. 

After you've done this, you can safely delete the .egg files or directories,
along with any scripts you wish to remove. 

 For more information on how to use easy_install:
[http://peak.telecommunity.com/DevCenter/EasyInstall](http://peak.telecommunity.com/DevCenter/EasyInstall "EasyInstall") 

>>> while True print 'Hello world'
  File "", line 1, in ?
    while True print 'Hello world'
                   ^
SyntaxError: invalid syntax 

>>> 10 * (1/0)
Traceback (most recent call last):
  File "", line 1, in ?
ZeroDivisionError: integer division or modulo by zero
>>> 4 + spam*3
Traceback (most recent call last):
  File "", line 1, in ?
NameError: name 'spam' is not defined
>>> '2' + 2
Traceback (most recent call last):
  File "", line 1, in ?
TypeError: cannot concatenate 'str' and 'int' objects 

 filename = "hello.txt"
file = open(filename, "r")
for line in file:
   print line, 

 read()		#return one big string
readline	#return one line at a time
read-lines 	#returns a list of lines 

 write ()	#Used to write a fixed sequence of characters to a file

writelines()	#writelines can write a list of strings. 

 To open a text file, use:
fh = open("hello.txt", "r")

To read a text file, use:
fh = open("hello.txt","r")
print fh.read()

To read one line at a time, use:
fh = open("hello".txt", "r")
print fh.readline()

To read a list of lines use:
fh = open("hello.txt.", "r")
print fh.readlines()

To [write to a file](https://www.pythonforbeginners.com/files/reading-and-writing-files-in-python), use:
fh = open("hello.txt","w")
write("Hello World")
fh.close()

To [write to a file](https://www.pythonforbeginners.com/files/reading-and-writing-files-in-python), use:
fh = open("hello.txt", "w")
lines_of_text = ["a line of text", "another line of text", "a third line"]
fh.writelines(lines_of_text)
fh.close()

To append to file, use:
fh = open("Hello.txt", "a")
write("Hello World again")
fh.close()

To close a file, use
fh = open("hello.txt", "r")
print fh.read()
fh.close() 

def numbers(num1, num2): 

    print num1+num2 

def name():
    # Get the user's name.
    name = raw_input('Enter your name: ') 

    # Return the name.
    return name         

name() 

def even(number):        
    if number % 2 == 0:
        return True

    else:
        return False

print even(10) 

def print_options():
    print "Options:"
    print " 'p' print options"
    print " 'c' convert from celsius"
    print " 'f' convert from fahrenheit"
    print " 'q' quit the program"

def celsius_to_fahrenheit(c_temp):
    return 9.0 / 5.0 * c_temp + 32

def fahrenheit_to_celsius(f_temp):
    return (f_temp - 32.0) * 5.0 / 9.0

choice = "p"

while choice != "q":

    if choice == "c":
        temp = input("Celsius temperature: ")
        print "Fahrenheit:", celsius_to_fahrenheit(temp)

    elif choice == "f":
        temp = input("Fahrenheit temperature: ")
        print "Celsius:", fahrenheit_to_celsius(temp)

    elif choice != "q":
        print_options()

    choice = raw_input("option: ") 

import random 

number = random.randint(1, 99) 

guesses = 0 

while guesses < 5:
    guess = int(raw_input("Enter an integer from 1 to 99: "))
    guesses +=1
    print "this is your %d guess" %guesses 

 if guess < number:
        print "guess is low"
    elif guess > number:
        print "guess is high"
    elif guess == number:
        break 

if guess == number:
    guesses = str(guesses)
    print "You guess it in : ", guesses + " guesses" 

if guess != number:
    number = str(number)
    print "The secret number was",  number 

import random
n = random.randint(1, 99)
guess = int(input("Enter an integer from 1 to 99: "))
while True:
    if guess < n:
        print ("guess is low")
        guess = int(input("Enter an integer from 1 to 99: "))
    elif guess > n:
        print ("guess is high")
        guess = int(input("Enter an integer from 1 to 99: "))
    else:
        print ("you guessed it right! Bye!")
        break

Enter an integer from 1 to 99: 23
guess is low
Enter an integer from 1 to 99: 45
guess is low
Enter an integer from 1 to 99: 67
guess is low
Enter an integer from 1 to 99: 89
guess is low
Enter an integer from 1 to 99: 98
you guessed it right! Bye!

sudo apt-get update

sudo apt-get install idle

Python 3.8.10 (default, Mar 15 2022, 12:22:08) 
[GCC 9.4.0] on linux 
Type "help", "copyright", "credits" or "license()" for more information.

2 < 5
3 > 7
x = 11
x > 10
2 * x < x
type(True)

If ...else

    if condition:
        statements

    elif condition:
 statements

    else:
 statements

x = raw_input("What is the time?")

if x < 10:
 print "Good morning"

elif x<12: 
 print "Soon time for lunch"

elif x<18: 
  print "Good day"

elif x<22: 
 print "Good evening"

else: 
  print "Good night"

# Allowed users to login
allowed_users = ['bill', 'steve']

# Get the username from a prompt
username = raw_input("What is your login? :  ")

# Control if the user belongs to allowed_users

if username in allowed_users:
    print "Access granted"

else:
    print "Access denied"

if :
    [do something]
    ....
    ....
elif [another statement is true]:
    [do something else]
    ....
    ....
else:
    [do another thing]
    ....
    .... 

import sys    		
# access module, after this you can use sys.name to refer to
# things defined in module sys.

from sys import stdout  
# access module without qualifying name. 
# This reads >> from the module "sys" import "stdout", so that
# we would be able to refer "stdout" in our program.

from sys import *       
# access all functions/classes in the sys module. 

Python 2.7.3 (default, Apr 20 2012, 22:39:59) 
[GCC 4.6.3] on linux2
Type "help", "copyright", "credits" or "license" for more information.

>>> the_world_is_flat = 1
>>> if the_world_is_flat:
...     print "Be careful not to fall off!"
... 

import os
os.system('ls -l') 

>>> music = ["Abba","Rolling Stones","Black Sabbath","Metallica"]

>>> print music
['Abba', 'Rolling Stones', 'Black Sabbath', 'Metallica'] 

>>> print ' '.join(music)
Abba Rolling Stones Black Sabbath Metallica 

>>> print "
".join(music)
Abba
Rolling Stones
Black Sabbath
Metallica 

>>> print "	".join(music)
Abba	Rolling Stones	Black Sabbath	Metallica
>>> 

myDict = {1: 1, 2: 4, 3: 9}
print("The dictionary is:", myDict)
print(myDict[4]) 

The dictionary is: {1: 1, 2: 4, 3: 9}
Traceback (most recent call last):
  File "/home/aditya1117/PycharmProjects/pythonProject/string.py", line 3, in <module>
    print(myDict[4])
KeyError: 4

myDict = {1: 1, 2: 4, 3: 9}
print("The dictionary is:", myDict)
key = 4
if key in myDict.keys():
    print(myDict[key])
else:
    print("{} not a key of dictionary".format(key)) 

The dictionary is: {1: 1, 2: 4, 3: 9}
4 not a key of dictionary

myDict = {1: 1, 2: 4, 3: 9}
print("The dictionary is:", myDict)
key = 3
print("Key is:",key)
print("Value associated to the key is:",myDict.get(key)) 

The dictionary is: {1: 1, 2: 4, 3: 9}
Key is: 3
Value associated to the key is: 9

myDict = {1: 1, 2: 4, 3: 9}
print("The dictionary is:", myDict)
key = 4
print("Key is:",key)
print("Value associated to the key is:",myDict.get(key)) 

 The dictionary is: {1: 1, 2: 4, 3: 9}
Key is: 4
Value associated to the key is: None

myDict = {1: 1, 2: 4, 3: 9}
print("The dictionary is:", myDict)
key = 4
print("Key is:",key)
print("Value associated to the key is:",myDict.get(key,16)) 

The dictionary is: {1: 1, 2: 4, 3: 9}
Key is: 4
Value associated to the key is: 16

myDict = {1: 1, 2: 4, 3: 9}
print("The dictionary is:", myDict)
key=4
print("Key is:",key)
try:
    val=myDict[key]
    print("Value associated to the key is:",val)
except KeyError:
    print("Key not present in Dictionary") 

The dictionary is: {1: 1, 2: 4, 3: 9}
Key is: 4
Key not present in Dictionary

myList = [1,2,3,5,8,2,5.2] 
i = 0
while i < len(myList):
    print myList[i]
    i = i + 1 

 Output >> 1 2 3 5 8 2 5.2 

list1 = [1,2,3,5,8,2,5.2]
total = 0
i = 0
while i < len(list1):
    total = total + list1[i]
    i = i + 1

average = total / len(list1)
print average 

#Output >> 3.74285714286

 Creation
L = ['yellow', 'red', 'blue', 'green', 'black']
>>>print L
returns: ['yellow', 'red', 'blue', 'green', 'black']

##########

Accessing / Indexing
L[0]  = returns 'yellow'

##########

Slicing
L[1:4]  = returns ['red', 'blue', 'green']
L[2:] 	= returns ['blue', 'green', 'black']
L[:2] 	= returns ['yellow', 'red']
L[-1]  	= returns 'black'
L[1:-1] = returns ['red', 'blue', 'green']

##########

Length - number of items in list
len(L)  = returns 5

##########

Sorting - sorting the list
sorted(L) = returns ['black', 'blue', 'green', 'red', 'yellow']

##########

Append - append to end of list
L.append("pink")

>>> print L
returns: ['black', 'blue', 'green', 'red', 'yellow', 'pink']

##########

Insert - insert into list
L.insert(0, "white")

>>> print L
returns: ['white', 'black', 'blue', 'green', 'red', 'yellow', 'pink']

##########

Extend - grow list

L.extend(L2)

##########

Remove - remove first item in list with value "white"

L.remove("white")

>>> print L
returns: ['black', 'blue', 'green', 'red', 'yellow', 'pink']

##########

Delete

Remove an item from a list given its index instead of its value
del.L[0]

>>> print L
['blue', 'green', 'red', 'yellow', 'pink']

##########

Pop

Remove last item in the list
L.pop()  = returns 'pink'

# remove indexed value from list
L.pop(1) = returns 'green'  

##########

Reverse - reversing the list
L.reverse()

##########

Count

Search list and return number of instances found
L.count('red')

##########

Keyword "in" - can be used to test if an item is in a list

if 'red' in L:
    print "list contains", 'red'

##########

For-in statement - makes it easy to loop over the items in a list
for item in L:
    print item

L = ['red', 'blue', 'green']
for col in L:
    print col 

>>> list1 = ["Movies", "Music", "Pictures"]

#list1.append(x) will add an element to the end of the list
>>> list1.append("Files")
>>> list1
['Movies', 'Music', 'Pictures', 'Files']

#list1.insert(x, y) will add element y on the place before x
>>> list1.insert(2,"Documents")
>>> list1
['Movies', 'Music', 'Documents', 'Pictures', 'Files']

#list1.remove(x) will remove the element x from the list
>>> list1.remove("Files")
>>> list1
['Movies', 'Music', 'Documents', 'Pictures']

#list1.extend(x) will join the list with list x
>>> list2 = ["Music2", "Movies2"]
>>> list1.extend(list2)
>>> list1
['Movies', 'Music', 'Documents', 'Pictures', 'Music2', 'Movies2'] 

# a list for days of the work week
weekdays = ["Monday","Tuesday","Wednesday","Thursday","Friday"]

# an empty list just waiting to do something
empty_list = []

# lists can hold data of different types
mix_list = ["one","two",1,2] 

nums = [0,1,2,3,4,5,6,7,8,9]
# print the total number of items in the list
print("Length of the list: ", len(nums)) 

Length of the list:  10

# a list of popular car manufacturers
car_brands = ["BMW","Ford","Toyota","GM","Honda","Chevrolet"]

# add to a list with append()
car_brands.append("Tesla") 

letters = ['B','C','D','E','F','G']
letters.insert(0,'A') # add element 'A' at the first index

print(letters) 

['A', 'B', 'C', 'D', 'E', 'F', 'G']

my_list.insert(x,y) # this will insert y before x

# an example of inserting an element into the third position in a list
top_five = ["The Beatles","Marvin Gaye","Gorillaz","Cat Power"]
top_five.insert(2, "Prince")

print(top_five)

 ['The Beatles', 'Marvin Gaye', 'Prince', 'Nirvana', 'Cat Power']

# a basic to do list
to_do = ["dishes","laundry","dusting","feed the dog"]
# we already fed Fido!
to_do.remove("feed the dog")
print("Things to do: ", to_do)

# remove the first 3 in the list
nums = [1,2,3,3,4,5]
nums.remove(3)
print(nums)

Things to do:  ['dishes', 'laundry', 'dusting']
[1, 2, 3, 4, 5] 

# we need a list of items to send to the  movers
furniture = ["bed","chair","bookcase"]

# add additional elements with extend()
furniture.extend(["couch","desk","coffee table"])
print(furniture) 

['bed', 'chair', 'bookcase', 'couch', 'desk', 'coffee table']

nums = [1,2,3,4]
nums.pop(1)
print(nums) 

[1, 3, 4]

# generate a list of numbers 1-10
nums = [x for x in range(1,11)]
# pop the last element off the list
nums.pop()
print(nums) 

[1, 2, 3, 4, 5, 6, 7, 8, 9]

list_item in list

the_beatles = ["John","Paul","George","Ringo"]
print("Was John in the Beatles? ","John" in the_beatles)

Was John in the Beatles?  True

print("So Yoko wasn't a member of the Beatles? ","Yoko" not in the_beatles)

So Yoko wasn't a member of the Beatles?  True

superheroes = ["Batman", "The Black Panther", "Iron Man"]

# use slice notation to traverse the list in reverse
for hero_name in superheroes[::-1]:
    print(hero_name)

# use the reverse method to reverse a list in place
superheroes.reverse()

print(superheroes) 

Iron Man
The Black Panther
Batman
['Iron Man', 'The Black Panther', 'Batman']

nums = [100,2003,1997,3,-9,1]

nums.sort()
print(nums) 

[-9, 1, 3, 100, 1997, 2003]

alphabet = ['B','C','A']

alphabet.sort()
print(alphabet) 

['A', 'B', 'C']

nums = [7,2,42,99,77]
# sorted will return a new list
print("Modified list:", sorted(nums))
print("Original list: ", nums) 

Modified list: [2, 7, 42, 77, 99]
Original list:  [7, 2, 42, 99, 77] 

villains = ["Shredder","Darth Vader","The Joker"]

print(villains[0])
print(villains[1])
print(villains[2]) 

Shredder
Darth Vader
The Joker 

# swamp the first and third items of the list
temp = villains[2]
villains[2] = villains[0]
villains[0] = temp 

# swap list items with the power of Python!
villains[0],villains[2]=villains[2],villains[0] 

my_list[start:end:step] 

rainbow = ['red','orange','yellow','green','blue','indigo','violet']
print(rainbow[1]) # get the second item in the list
print(rainbow[:1]) # get items at indexes 0 and 1
print(rainbow[1:3]) # items at index 1 and 2
print(rainbow[:-1]) # all items excluding the last 

orange
['red']
['orange', 'yellow']
['red', 'orange', 'yellow', 'green', 'blue', 'indigo'] 

# a list of random numbers in ascending order
nums = [2,4,7,8,9,10,11,12,13,15,16,17]
# a list of prime numbers
primes = [2,3,5,7,11,13,17]

# loop through a Python list
for num in nums:
    if num in primes:
        print(num,end=" ") 

2 7 11 13 17

nums = [98,62,77,84,89]

total = 0
for i in range(len(nums)):
    total += nums[i]

print("Total: ", total) 

Total:  410

# find the average for a list of numbers
nums = [20,22,1.5,2,7,5.2,99]

total = 0
i = 0
while i < len(nums):
    total = total + nums[i]
    i = i + 1

average = total/len(nums)
print("The average to 2 decimal places: {:.2f}".format(average)) 

The average to 2 decimal places: 22.39

emptyList = [ ]  

list1 = ['one, two, three, four, five']

numlist = [1, 3, 5, 7, 9]

mixlist = ['yellow', 'red', 'blue', 'green', 'black']

#An empty list is created using just square brackets:
list = []

list = ["1", "hello", 2, "world"]
len(list)
>>4

list.insert(0, "Files")

list = ["Movies", "Music", "Pictures"]

list.append(x) #will add an element to the end of the list
list.append("Files")

print list
['Movies', 'Music', 'Pictures', 'Files’]

list.insert(x, y) 	#will add element y on the place before x

list = ["Movies", "Music", "Pictures"] 

list.insert(2,"Documents")

print list
['Movies', 'Music', 'Documents', 'Pictures', 'Files']

#You can insert a value anywhere in the list

list = ["Movies", "Music", "Pictures"] 
list.insert(3, "Apps”)

list.remove(x)

List = ['Movies', 'Music', 'Files', 'Documents', 'Pictures']

list.remove("Files")

print list
['Movies', 'Music', 'Documents', 'Pictures']

a = [1, 2, 3, 4]
a.remove(2)
print a
[1, 3, 4]

list.extend(x) 	#will join the list with list x

list2 = ["Music2", "Movies2"]
list1.extend(list2)

print list1
['Movies', 'Music', 'Documents', 'Pictures', 'Music2', 'Movies2’]

list = ["Matthew", "Mark", "Luke", "John"]
del list[1]

print list
>>>Matthew, Luke, John

list = ["red", "orange", "green", "blue"]
if "red" in list:
    do_something()

#Keyword "not" can be combined with "in".

list = ["red", "orange", "green", "blue"]
if "purple" not in list:
    do_something()

L1 = ["One", "two", "three", "four", "five"]

#To print the list as it is, simply do:
print L1

#To print a reverse list, do:
for i in L1[::-1]:
    print i

#OR

L = [0, 10, 20, 40]
L.reverse()

print L
[40, 20, 10, 0]

#create a list with some numbers in it
numbers = [5, 1, 4, 3, 2, 6, 7, 9]

#prints the numbers sorted
print sorted(numbers)

#the original list of numbers are not changed
print numbers
my_string = ['aa', 'BB', 'zz', 'CC', 'dd', "EE"]

#if no argument is used, it will use the default (case sensitive)
print sorted(my_string)

#using the reverse argument, will print the list reversed
print sorted(strs, reverse=True)   ## ['zz', 'aa', 'CC', 'BB']

This will not return a value, it will modify the list
list.sort()

mylist = ['one', 'two', 'three', 'four', 'five']
newlist = mylist.split(',')

print newlist
['one', ' two', ' three', ' four', 'five’]

list 	= ["first", "second", "third"]
list[0] == "first"
list[1] == "second"
list[2] == "third”

colors = ['yellow', 'red', 'blue', 'green', 'black']

print colors[0]
>>> yellow

print colors [1:]
>>> red, blue, green, black

a[start:end] 			# items start through end-1
a[start:]    			# items start through the rest of the array
a[:end]      			# items from the beginning through end-1
a[:]         			# a copy of the whole array

a[start:end:step] 		# start through not past end, by step

a[-1]    			# last item in the array
a[-2:]   			# last two items in the array
a[:-2]   			# everything except the last two items

#It can look something like this:
matching = []
for term in mylist:
    do something

#For example, you can add an if statement in the loop, and add the item to the (empty) list
if it's matching.
matching = []    #creates an empty list using empty square brackets []
for term in mylist:
    if test(term):
        matching.append(term)

#If you already have items in a list, you can easily loop through them like this:
items = [ 1, 2, 3, 4, 5 ]
for i in items:
    print i

s = ['h','e','l','l','o']	#create a list
s.append('d')         		#append to end of list
len(s)                		#number of items in list
s.sort()               		#sorting the list
s.reverse()           		#reversing the list
s.extend(['w','o'])    		#grow list
s.insert(1,2)         		#insert into list
s.remove('d')           	#remove first item in list with value e
s.pop()               		#remove last item in the list
s.pop(1)              		#remove indexed value from list
s.count('o')            	#search list and return number of instances found
s = range(0,10)          	#create a list over range 
s = range(0,10,2)        	#same as above, with start index and increment

list = [1,2,3,5,8,2,5.2]	#creates a list containing the values 1,2,3,5,8,2,5.2
i = 0
while i < len(list):		#The while loop will print each element in the list
    print list[i]		 #Each element is reached by the index (the letter in the square bracket)
    i = i + 1			 #Increase the variable i with 1 for every time the while loop runs.

list = [1,2,3,5,8,2,5.2]
total = 0
i = 0
while i < len(list):
    total = total + list[i]
    i = i + 1

average = total / len(list)
print average

myString="This is a single line string"
anotherString='This is also a single line string'

myString="""This is
a
multiline string.
"""

myNum=1117

myNum=0b10101

myNum=0x123ab

myNum=0o124

myNum=123.345

myNum=3+4j

myVar=True
myVar1=False

myObj=None

myList=[1,2,"pfb",3.14]

myStr="I am a single line string"
myList=myStr.split()
print("String literal is:",myStr)
print("Created list is:",myList)

String literal is: I am a single line string
Created list is: ['I', 'am', 'a', 'single', 'line', 'string']

myTuple=(1,2,"pfb",3.14)

myDict={1:1,2:"pfb","name":'Chris', "Value":100.5}

mySet={1,2,"pfb",3.14}

import mechanize
br = mechanize.Browser()
br.set_all_readonly(False)    # allow everything to be written to
br.set_handle_robots(False)   # ignore robots
br.set_handle_refresh(False)  # can sometimes hang without this
br.addheaders =   	      	# [('User-agent', 'Firefox')] 

response = br.open(url)
print response.read()      # the text of the page
response1 = br.response()  # get the response again
print response1.read()     # can apply lxml.html.fromstring() 

for form in br.forms():
    print "Form name:", form.name
    print form 

br.select_form("form1")         # works when form has a name
br.form = list(br.forms())[0]  # use when form is unnamed 

for control in br.form.controls:
    print control
    print "type=%s, name=%s value=%s" % (control.type, control.name, br[control.name]) 

control = br.form.find_control("controlname") 

if control.type == "select":  # means it's class ClientForm.SelectControl
    for item in control.items:
    print " name=%s values=%s" % (item.name, str([label.text  for label in item.get_labels()])) 

print control.value
print control  # selected value is starred
control.value = ["ItemName"]
print control
br[control.name] = ["ItemName"]  # equivalent and more normal 

if control.type == "text":  # means it's class ClientForm.TextControl
    control.value = "stuff here"
br["controlname"] = "stuff here"  # equivalent 

control.readonly = False
control.disabled = True 

for control in br.form.controls:
   if control.type == "submit":
       control.disabled = True 

 response = br.submit()
print response.read()
br.back()   # go back 

for link in br.links():
    print link.text, link.url 

request = br.click_link(link)
response = br.follow_link(link)
print response.geturl() 

import urllib2

req = urllib2.Request('http://192.168.1.2/')

req.add_header('User-agent', 'Mozilla 5.10')

res = urllib2.urlopen(req)

html = res.read() 

 "GET / HTTP/1.1" 200 151 "-" "Mozilla 5.10" 

import sys    		
#access module, after this you can use sys.name to refer to things defined in module sys.

from sys import stdout  
# access module without qualiying name. 
This reads from the module "sys" import "stdout", so that we would be able to 
refer "stdout"in our program.

from sys import *       
# access all functions/classes in the sys module. 

Import sys
try:
    import BeautifulSoup
except ImportError:
    print 'Import not installed'
    sys.exit() 

testList = ["first", "second", "third"]
testDict = {0:"first", 1:"second", 2:"third"} 

>> phonenumbers = {'Jack':'555-555', 'Jill':'555-556'} 

phonebook = {}
phonebook["Jack"] = "555-555"
phonebook["Jill"] = "555-556"

print phonebook
{'Jill': '555-556', 'Jack': '555-555'} 

phonebook = {}
phonebook["Jack"] = "555-555"
phonebook["Jill"] = "555-556"

print phonebook['Jill']
555-556 

 To add a key / value pair in a dictionary
>>phonebook["Matt"] = "555-557"

To change a key / value pair:
>>phonebook["Jack"] = '555-558'

To remove a key / value pair, use del
 >>del phonebook["Jill"]

To see if a key exists, use has_key() method
>>phonebook.has_key("Matt")

To copy whole dictionary, use the copy() method
phonebook2 = phonebook.copy() 

import os
items = os.listdir(".")

newlist = []
for names in items:
    if names.endswith(".txt"):
        newlist.append(names)
print newlist

 root :	Prints out directories only from what you specified
dirs :	Prints out sub-directories from root. 
files:  Prints out all files from root and directories 

import os
print "root prints out directories only from what you specified"
print "dirs prints out sub-directories from root"
print "files prints out all files from root and directories"
print "*" * 20
for root, dirs, files in os.walk("/var/log"):
    print root
    print dirs
    print files 

print "This is using getsize to see how much every file consumes"
print "---------------"
from os.path import join, getsize
for root, dirs, files in os.walk('/tmp'):
    print root, "consumes",
    print sum([getsize(join(root, name)) for name in files]),
    print "bytes in", len(files), "non-directory files" 

 Pip is a replacement for easy_install. 

Packages installs the packages default under site-packages. 

 To install Pip on your system, you can use either the source tarball or
by using easy_install.
>> $ easy_install pip

After that, the pip application is installed. 

 How to use Pip 

$ pip install simplejson
[... progress report ...]
Successfully installed simplejson

$ pip install --upgrade simplejson
[... progress report ...]
Successfully installed simplejson

$ pip uninstall simplejson
Uninstalling simplejson:
  /home/me/env/lib/python2.7/site-packages/simplejson
  /home/me/env/lib/python2.7/site-packages/simplejson-2.2.1-py2.7.egg-info
Proceed (y/n)? y
  Successfully uninstalled simplejson

#Search PyPI for packages
$ pip search "query"

# To get info about an installed package, including its location and files:
pip show ProjectName

 (The answer is taken from this [post](https://stackoverflow.com/questions/3220404/why-use-pip-over-easy-install "pip-over-easy_install") on stackoverflow)

All packages are downloaded before installation. 

Partially-completed installation doesn’t occur as a result.

Care is taken to present useful output on the console.

The reasons for actions are kept track of. 

For instance, if a package is being installed, pip keeps track of why that 
package was required.

Error messages should be useful.

The code is relatively concise and cohesive, making it easier to use 
programmatically.

Packages don’t have to be installed as egg archives, they can be installed flat.

Native support for other version control systems (Git, Mercurial and Bazaar)

Uninstallation of packages.

Simple to define fixed sets of requirements and reliably reproduce a set of 
packages. 

>>> range(1,10)
[1, 2, 3, 4, 5, 6, 7, 8, 9]

# You can use range() wherever you would use a list. 

a = range(1, 10) 
for i in a: 
    print i 

for a in range(21,-1,-2):
   print a,

#output>> 21 19 17 15 13 11 9 7 5 3 1

# We can use any size of step (here 2)
>>> range(0,20,2)
[0, 2, 4, 6, 8, 10, 12, 14, 16, 18]

>>> range(20,0,-2)
[20, 18, 16, 14, 12, 10, 8, 6, 4, 2]

# The sequence will start at 0 by default. 
#If we only give one number for a range this replaces the end of range value.
>>> range(10)
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

# If we give floats these will first be reduced to integers. 
>>> range(-3.5,9.8)
[-3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8] 

builtin_names = dir(__builtins__)
for name in builtin_names:
    print(name)

ArithmeticError
AssertionError
AttributeError
BaseException
BlockingIOError
BrokenPipeError
BufferError
BytesWarning
ChildProcessError
ConnectionAbortedError
ConnectionError
ConnectionRefusedError
ConnectionResetError
DeprecationWarning
EOFError
Ellipsis
EnvironmentError
Exception
False
FileExistsError
FileNotFoundError
FloatingPointError
FutureWarning
GeneratorExit
IOError
ImportError
ImportWarning
IndentationError
IndexError
InterruptedError
IsADirectoryError
KeyError
KeyboardInterrupt
LookupError
MemoryError
ModuleNotFoundError
NameError
None
NotADirectoryError
NotImplemented
NotImplementedError
OSError
OverflowError
PendingDeprecationWarning
PermissionError
ProcessLookupError
RecursionError
ReferenceError
ResourceWarning
RuntimeError
RuntimeWarning
StopAsyncIteration
StopIteration
SyntaxError
SyntaxWarning
SystemError
SystemExit
TabError
TimeoutError
True
TypeError
UnboundLocalError
UnicodeDecodeError
UnicodeEncodeError
UnicodeError
UnicodeTranslateError
UnicodeWarning
UserWarning
ValueError
Warning
ZeroDivisionError
__build_class__
__debug__
__doc__
__import__
__loader__
__name__
__package__
__spec__
abs
all
any
ascii
bin
bool
breakpoint
bytearray
bytes
callable
chr
classmethod
compile
complex
copyright
credits
delattr
dict
dir
divmod
enumerate
eval
exec
exit
filter
float
format
frozenset
getattr
globals
hasattr
hash
help
hex
id
input
int
isinstance
issubclass
iter
len
license
list
locals
map
max
memoryview
min
next
object
oct
open
ord
pow
print
property
quit
range
repr
reversed
round
set
setattr
slice
sorted
staticmethod
str
sum
super
tuple
type
vars
zip

myNum1 = 10
myNum2 = 10

def add(num1, num2):
    temp = num1 + num2

    def print_sum():
        print(temp)

    return temp 

myNum1 = 10
myNum2 = 10

def add(num1, num2):
    temp = num1 + num2

    def print_sum():
        print(temp)

    return temp 

myNum1 = 10
myNum2 = 10

def add(num1, num2):
    temp = num1 + num2

    def print_sum():
        print(temp)

    return temp 

 This script will show all entries in the file that is specified in the log file
variable. 

 In this example, I will use the /var/log/syslog file. 

The for loop will go through each line of the log file and the line_split variablewill split it by lines. 

If you just print the line_split, you will see an output similar to this:

>> ['Sep', '27', '15:22:15', 'Virtualbox', 'NetworkManager[710]:', '<info>', 'DNS:'..']

If you want to print each element just add the line_split[element_to_show]

#!/usr/bin/env python
logfile = open("/var/log/syslog", "r")
for line in logfile:
    line_split = line.split()
    print line_split
    list = line_split[0], line_split[1], line_split[2], line_split[4]
    print list

 That's it, now you have a script that you can use for checking log files with. 

 This small script will count the number of hits in a Apache/Nginx log file. 

 This script can easily be adapted to any other log file. 

The script starts with making an empty dictionary for storing the IP addresses andcount how many times they exist. 

Then we open the file (in this example the Nginx access.log file) and read the
content line by line. 

The for loop go through the file and splits the strings to get the IP address. 

The len() function is used to ensure the length of IP address. 

If the IP already exists , increase by 1. 

ips = {}

fh = open("/var/log/nginx/access.log", "r").readlines()
for line in fh:
    ip = line.split(" ")[0]
    if 6 < len(ip) <=15:
        ips[ip] = ips.get(ip, 0) + 1
print ips

 If you now browse to your website, and run the python script, you should see your IP address + the counts. 

# Search for pysftp
pip search pysftp

pysftp                    # - A friendly face on SFTP

#Install pysftp
pip install pysftp 

import pysftp

srv = pysftp.Connection(host="your_FTP_server", username="your_username",
password="your_password")

# Get the directory and file listing
data = srv.listdir()

# Closes the connection
srv.close()

# Prints out the directories and files, line by line
for i in data:
    print i 

import pysftp
import sys

# Defines the name of the file for download / upload
remote_file = sys.argv[1]

srv = pysftp.Connection(host="your_FTP_server", username="your_username",
password="your_password")

# Download the file from the remote server
srv.get(remote_file)

# To upload the file, simple replace get with put. 
srv.put(remote_file)

# Closes the connection
srv.close() 

??$ python
Python 2.7.2 (default, Jun 20 2012, 16:23:33) 
[GCC 4.2.1 Compatible Apple Clang 4.0 (tags/Apple/clang-418.0.60)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> 

>>> 1 + 1
2
>>> you can type expressions here .. use ctrl-d to exit 

 When you want to extract part of a string, or some part of a list, you use a slice

The first character in string x would be x[0] and the nth character would be at
x[n-1]. 

Python also indexes the arrays backwards, using negative numbers. 

The last character has index -1, the second to last character has index -2. 

 x = "my string"

x[start:end] 	# items start through end-1
x[start:]    	# items start through the rest of the list
x[:end]      	# items from the beginning through end-1
x[:]         	# a copy of the whole list

One way to remember how slices work is to think of the indices as pointing betweencharacters, with the left edge of the first character numbered 0\. 

Then the right edge of the last character of a string of n characters has index n

 +---+---+---+---+---+
 | H | e | l | p | A |
 +---+---+---+---+---+
 0   1   2   3   4   5
-5  -4  -3  -2  -1

The first row of numbers gives the position of the indices 0...5 in the string, 
the second row gives the corresponding negative indices. 

 print socket.getfqdn("8.8.8.8")
>>google-public-dns-a.google.com 

 print socket.gethostbyname("www.python.org")
>>82.94.164.162 

 print socket.gethostbyname_ex("www.python.org")
>>('python.org', [], ['82.94.164.162']) 

 print socket.gethostname()
>>Virtualbox123 

 The script below, will return the IP address of the hostname given. 

If it cannot find the hostname, it will print the error to screen using 
the exception handling "gaierror" (raised for address-related errors). 

import socket
name = "wwaxww.python.org"
try:
    host = socket.gethostbyname(name)
    print host
except socket.gaierror, err:
    print "cannot resolve hostname: ", name, err

 If you look in the name, I misspelled the address to let you see how the error
message would look like

>>cannot resolve hostname:  wwaxww.python.org [Errno -5] No address associated
with hostname

And if I run it again with the correct spelling 

import socket
name = "www.python.org"
try:
    host = socket.gethostbyname(name)
    print host
except socket.gaierror, err:
    print "cannot resolve hostname: ", name, err

 >>82.94.164.162 

 The easiest way to sort is with the sorted(list) function, which takes a list and returns a new list with those elements in sorted order. 

The original list is not changed. 

The sorted() function can be customized though optional arguments. 

The sorted() optional argument reverse=True, e.g. sorted(list, reverse=True), 
makes it sort backwards. 

 Sorting Examples 

 **Create a list with some numbers in it** numbers = [5, 1, 4, 3, 2, 6, 7, 9]

**prints the numbers sorted** print sorted(numbers)

**the original list of numbers are not changed** print numbers

my_string = ['aa', 'BB', 'zz', 'CC', 'dd', "EE"]

**if no argument is used, it will use the default (case sensitive)** print sorted(my_string)

**using the reverse argument, will print the list reversed** print sorted(strs, reverse=True)   ## ['zz', 'aa', 'CC', 'BB'] 

 Please see the [python wiki](https://wiki.python.org/moin/HowTo/Sorting/ "wki-sorting") for more things to do with sorting. 

 This is a simple script to split the domain name from a URL. It does that by usingPythons urlparse module. 

import urlparse
url = "http://python.org"
domain = urlparse.urlsplit(url)[1].split(':')[0]
print "The domain name of the url is: ", domain

*x* *= ‘**blue,red**,green**’*
*x.**split**(**“,”)*

*[‘blue’, ‘red’, ‘green’]*
*>>>*

*>>>* *a,b**,c* *=* *x.split**(“,”)*

*>>> a*
*‘blue’*

*>>> b* 
*‘red’*

*>>> c*
*‘green’*

*>>> words = “This is random text we’re going to split apart”*

*>>> words2 =* *words.split**(“ “)*

*>>> words2* 
*[‘This’, ‘is’, ‘random’, ‘text’, ‘we’re’, ‘going’, ‘to’, ‘split’, ‘apart’]*

 %a 	Locale’s abbreviated weekday name.
%A 	Locale’s full weekday name. 	 
%b 	Locale’s abbreviated month name. 	 
%B 	Locale’s full month name.
%c 	Locale’s appropriate date and time representation. 	 
%d 	Day of the month as a decimal number [01,31]. 	 
%f 	Microsecond as a decimal number [0,999999], zero-padded on the left
%H 	Hour (24-hour clock) as a decimal number [00,23]. 	 
%I 	Hour (12-hour clock) as a decimal number [01,12]. 	 
%j 	Day of the year as a decimal number [001,366]. 	 
%m 	Month as a decimal number [01,12]. 	 
%M 	Minute as a decimal number [00,59]. 	 
%p 	Locale’s equivalent of either AM or PM.
%S 	Second as a decimal number [00,61].
%U 	Week number of the year (Sunday as the first day of the week)
%w 	Weekday as a decimal number [0(Sunday),6]. 	 
%W 	Week number of the year (Monday as the first day of the week)
%x 	Locale’s appropriate date representation. 	 
%X 	Locale’s appropriate time representation. 	 
%y 	Year without century as a decimal number [00,99]. 	 
%Y 	Year with century as a decimal number. 	 
%z 	UTC offset in the form +HHMM or -HHMM.
%Z 	Time zone name (empty string if the object is naive). 	 
%% 	A literal '%' character.

myString="python"
print("Original String:")
print(myString)
newString=myString.capitalize()
print("New modified string:")
print(newString)
print("original string after modification:")
print(myString)

Original String:
python
New modified string:
Python
original string after modification:
python

myString="Python is a great language" 
newString=myString.title()
print("Original string is:")
print(myString)
print("Output is:")
print(newString)

Original string is:
Python is a great language
Output is:
Python Is A Great Language

myString="PytHon"
print("Original String:")
print(myString)
newString=myString.casefold()
print("New modified string:")
print(newString)
print("original string after modification:")
print(myString)

Original String:
PytHon
New modified string:
python
original string after modification:
PytHon

myString="PytHon"
print("Original String:")
print(myString)
newString=myString.lower()
print("New modified string:")
print(newString)
print("original string after modification:")
print(myString)

Original String:
PytHon
New modified string:
python
original string after modification:
PytHon

myString="PytHon"
print("Original String:")
print(myString)
newString=myString.upper()
print("New modified string:")
print(newString)
print("original string after modification:")
print(myString)

Original String:
PytHon
New modified string:
PYTHON
original string after modification:
PytHon

myString="PytHon"
print("Original String:")
print(myString)
newString=myString.swapcase()
print("New modified string:")
print(newString)
print("original string after modification:")
print(myString)

Original String:
PytHon
New modified string:
pYThON
original string after modification:
PytHon

myString="I am A Python String"
print("Original String:")
print(myString)
newList=myString.split()
print("New List:")
print(newList)
print("when 'A' is declared as separator:")
aList=myString.split("A")
print(aList)
print("original string after modification:")
print(myString)

Original String:
I am A Python String
New List:
['I', 'am', 'A', 'Python', 'String']
when 'A' is declared as separator:
['I am ', ' Python String']
original string after modification:
I am A Python String

myString="I am A Python String"
print("Original String:")
print(myString)
newList=myString.rsplit()
print("New List without maxsplit:")
print(newList)
print("when maxsplit is set at 2:")
aList=myString.rsplit(maxsplit=2)
print(aList)
print("original string after modification:")
print(myString)

Original String:
I am A Python String
New List without maxsplit:
['I', 'am', 'A', 'Python', 'String']
when maxsplit is set at 2:
['I am A', 'Python', 'String']
original string after modification:
I am A Python String

myString1="I am a "
print ("first string is:")
print(myString1)
myString2="Python String"
print("Second String is:")
print(myString2)
myString=myString1+myString2
print("Conactenated string is:")
print(myString)

myString1="I am a "
print ("first string is:")
print(myString1)
myString2="Python String"
print("Second String is:")
print(myString2)
myString=myString1+myString2
print("Conactenated string is:")
print(myString)

myStringList=["I","am","a","python","string"]
print ("list of string is:")
print(myStringList)
separator=" "#space is used as separator
myString=separator.join(myStringList)
print("Concatenated string is:")
print(myString)

list of string is:
['I', 'am', 'a', 'python', 'string']
Concatenated string is:
I am a python string

myString="          Python          " 
lstring=myString.lstrip()
rstring=myString.rstrip()
string =myString.strip()
print("Left Stripped string is:",end="")
print(lstring)
print("Right Stripped string is:",end="")
print(rstring)
print("Totally Stripped string is:",end="")
print(string)

Left Stripped string is:Python          
Right Stripped string is:          Python
Totally Stripped string is:Python 

myString="Python is a great language.\n I love python" 
slist=myString.splitlines()
print("Original string is:")
print(myString)
print("Output is:")
print(slist)

Original string is:
Python is a great language.
I love python
Output is:
['Python is a great language.', ' I love python']

string = "Hello World"

print string.isupper()
print string.upper()
print string.islower()
print string.isupper()
print string.capitalize()
print string.split()
print string.split(',')
print string.title()
print string.strip() 

False
HELLO WORLD
False
False
Hello world
['Hello', 'World']
['Hello World']
Hello World
Hello World 

$ python

print("Hello World”)

$ chmod +x test.py

$ python Hello_Python.py

"Hello, World”

import keyword

>>> keyword.kwlist 

['and', 'as', 'assert', 'break', 'class', 'continue', 'def', 'del', 'elif', 'else', 'except', 'exec', 'finally', 'for', 'from', 'global', 'if', 'import', 'in', 'is', 'lambda', 'not', 'or', 'pass', 'print', 'raise', 'return', 'try', 'while', 'with', 'yield'] 

person = ["Dave", "Ben", "Emily"]

for x in person:

if x == "Ben":

print(x)

else:

print("not Ben") 

List of Persons

    Go through the list of Persons:

See if Ben is there:

    If yes, print Ben's name

else:

    print that it's not Ben 

person="John Doe";age=12;location="unknown" 

 [-c cmd | -m mod | file | -] [arg] ...

Options and arguments (and corresponding environment variables):

-B     : don't write .py[co] files on import; also PYTHONDONTWRITEBYTECODE=x

-c cmd : program passed in as string (terminates option list)

-d     : debug output from parser; also PYTHONDEBUG=x

-E     : ignore PYTHON* environment variables (such as PYTHONPATH)

-h     : print this help message and exit (also --help)

-i     : inspect interactively after running script; forces a prompt even

if stdin does not appear to be a terminal; also PYTHONINSPECT=x

-m mod : run library module as a script (terminates option list)

-O     : optimize generated bytecode slightly; also PYTHONOPTIMIZE=x

-OO    : remove doc-strings in addition to the -O optimizations

-R     : use a pseudo-random salt to make hash() values of various types be

unpredictable between separate invocations of the interpreter, as

a defense against denial-of-service attacks

-Q arg : division options: -Qold (default), -Qwarn, -Qwarnall, -Qnew

-s     : don't add user site directory to sys.path; also PYTHONNOUSERSITE

-S     : don't imply 'import site' on initialization

-t     : issue warnings about inconsistent tab usage (-tt: issue errors)

-u     : unbuffered binary stdout and stderr; also PYTHONUNBUFFERED=x

see man page for details on internal buffering relating to '-u'

-v     : verbose (trace import statements); also PYTHONVERBOSE=x

can be supplied multiple times to increase verbosity

-V     : print the Python version number and exit (also --version)

-W arg : warning control; arg is action:message:category:module:lineno

also PYTHONWARNINGS=arg

-x     : skip first line of source, allowing use of non-Unix forms of #!cmd

-3     : warn about Python 3.x incompatibilities that 2to3 cannot trivially fix

file   : program read from script file

-      : program read from stdin (default; interactive mode if a tty)

arg ...: arguments passed to program in sys.argv[1:]

$ virtualenv newevironment 

source newenvironment 

pip install "package" 

pip install "package==2.801" 

pip install "package>=2.8" 

raw_input(): 

input() 

user_input_request = input("Enter your name: ") 

import sys
print "This is the name of the script: ", sys.argv[0]
print "Number of arguments: ", len(sys.argv)
print "The arguments are: " , str(sys.argv)

This is the name of the script: sysargv.py
Number of arguments in: 1
The arguments are: ['sysargv.py']

This is the name of the script: sysargv.py
Number of arguments in: 3
The arguments are: ['sysargv.py', 'arg1', 'arg2']

os.system()	# Executing a shell command

os.stat()	# Get the status of a file

os.environ()    # Get the users environment

os.chdir()   	# Move focus to a different directory

os.getcwd()    	# Returns the current working directory

os.getgid()    	# Return the real group id of the current process

os.getuid()    	# Return the current process’s user id

os.getpid()     # Returns the real process ID of the current process

os.getlogin()   # Return the name of the user logged

os.access()   	# Check read permissions

os.chmod()    	# Change the mode of path to the numeric mode

os.chown()   	# Change the owner and group id

os.umask(mask)  # Set the current numeric umask

os.getsize()   	# Get the size of a file

os.environ()    # Get the users environment

os.uname()   	# Return information about the current operating system

os.chroot(path) # Change the root directory of the current process to path

os.listdir(path)# List of the entries in the directory given by path

os.getloadavg() # Show queue averaged over the last 1, 5, and 15 minutes

os.path.exists()# Check if a path exists

os.walk()   	# Print out all directories, sub-directories and files

os.mkdir(path)	# Create a directory named path with numeric mode mode

os.remove(path)	# Remove (delete) the file path

os.rmdir(path)  # Remove (delete) the directory path

os.makedirs(path)# Recursive directory creation function

os.removedirs(path) # Remove directories recursively

os.rename(src, dst) # Rename the file or directory src to dst

#Get current working directory with os.getcwd()
print os.getcwd()

#Get the status of a file with os.stat()
print "Getting the status of: ", os.stat('/usr/bin/python')

#Execute a shell command with os.system()
os.system('ls -l')

#Return the current process id with os.getpid()
print os.getpid()
os.chmod(path, mode)

#Change the owner and group id of path to the numeric uid and gid with os.chown()
os.chown(path, uid, gid)

#Processes in the system run queue averaged over the last 1, 5, and 15 minutes
print os.getloadavg()

#Check if a path exists with os.path.exists()
if os.path.exists("file.txt"):

#Create a new directory named 'new_directory' if it doesn't exist already"
os.path.exists("new_directory") or os.mkdir("new_directory")

#Check if the path is a directory or a file with os.path.isdir() & os.path.isfile()
path = "/tmp"
if os.path.isdir(path): print "That's a directory"
if os.path.isfile(path): print "That's a file"

#Create a directory with os.makedir()
print os.mkdir('new_directory', 0666)

#Recursive create directories with os.makedirs()
os.makedirs('dir_a/dir_b/dir_c')

#Remove a directory with os.rmdir()
print os.rmdir('directory')

#Recursively remove empty directories with os.rmdirs()
os.removedirs('dir_a/dir_b/dir_c')

#Rename a file with os.rename()
print os.rename('/path/to/old/file', '/path/to/new/file')

#Rename a file with shutil.move()
print shutil.move('/path/to/old/file', '/path/to/new/file')

#Rename a file with shutil.copy()
print shutil.copy('/path/to/old/file', '/path/to/new/file')

#Get the users home directory
print os.path.expanduser('~')

#Check read permissions with os.access()
path = '/tmp/file.txt'
print os.access(path, os.R_OK)

#Get the users environment with os.environmen()
home =  os.environ['HOME']
print home

#Move focus to a different directory with os.chdir()
print os.chdir('/tmp')

#Print out all directories, sub-directories and files with os.walk()
for root, dirs, files in os.walk("/tmp"):
    print root
    print dirs
    print files

#Get the last time a directory was accessed with os.path.getatime()
os.path.getatime('/tmp')

#Get the last time a directory was modified with os.path.getmtime()
os.path.getmtime('/tmp')

#Get the user ID with os.getuid()
if os.getuid() != 0: print "you are not root"

#Get the group ID with os.getgid()
print os.getgid()

#Return the name of the user logged in with os.getlogin()
print os.getlogin()

#Returns a list of all files in a directory with os.listdir()
for filename in os.listdir("/tmp"):
    print "This is inside /tmp", filename

#Get the size of a file with os.path.getsize()
path.getsize("/tmp/file.txt")

 # Basically the unix command cp src dst. 

# this copies the source file to the destination directory

# the destination directory has to exist

# if the filename already exists there, it will be overwritten

# access time and last modification time will be updated

# the same filename is used

# the permissions of the file are copied along with the contents.

import shutil
import os
source = os.listdir("/tmp/")
destination = "/tmp/newfolder/"
for files in source:
    if files.endswith(".txt"):
        shutil.copy(files,destination)

###########
shutil.copyfile ( src , dest )
# copy data from src to dest 

# both names must be files.

# copy files by name 
import shutil  
shutil.copyfile('/path/to/file', '/path/to/other/phile') 

############
shutil.move
# recursively move a file or directory (src) to another location (dst).

# if the destination is a directory or a symlink to a directory, then src is moved
inside that directory.

# the destination directory must not already exist.

# this would move files ending with .txt to the destination path
import shutil
import os
source = os.listdir("/tmp/")
destination = "/tmp/newfolder/"
for files in source:
    if files.endswith(".txt"):
        shutil.move(files,destination)

####################
shutil.copytree ( src , dest )
# recursively copy the entire directory tree rooted at src to dest. 

# dest must not already exist. 

# errors are reported to standard output.

####################
import shutil
import os
SOURCE = "samples"
BACKUP = "samples-bak"
# create a backup directory
shutil.copytree(SOURCE, BACKUP)
print os.listdir(BACKUP)

####################
shutil.rmtree ( path )

# recursively delete a directory tree.
# This removes the directory 'three' and anything beneath it in the filesystem.
import shutil
shutil.rmtree('one/two/three') 

try:
    print "Hello World"
except:
    print "This is an error message!"

except IOError:
    print('An error occured trying to read the file.')

except ValueError:
    print('Non-numeric data found in the file.')

except ImportError:
    print "NO module found"

except EOFError:
    print('Why did you do an EOF on me?')

except KeyboardInterrupt:
    print('You cancelled the operation.')

except:
    print('An error occured.')

 Tuple  is another data type in Python. 

A tuple consists of values separated by commas.

Tuples are always enclosed in parentheses.

Tuples are for immutable.

Though tuples may seem similar to lists, they are often used in different
situations and for different purposes. 

Empty tuples are constructed by an empty pair of parentheses.

Tuple with one item is constructed by following a value with a comma. 

 x = ()				# empty tuple
x = (0,)			# one item tuple
x = (0, 1, 2, "abc")            # four item tuple: indexed x[0]..x[3]
x = 0, 1, 2, "abc"              # parenthesis are optional
x = (0, 1, 2, 3, (1, 2))        # nested subtuples
y = x[0]		      	# indexed item
y = x[4][0]                    	# indexed subtuple
x = (0, 1) * 2                  # repeat
x = (0, 1, 2) + (3, 4)         	# concatenation
for item in x: print item    	# iterate through tuple
b = 3 in x			# test tuple membership 

 To make use of Telnet in Python, we can use the telnetlib module. 

That module provides a Telnet class that implements the Telnet protocol.

The Telnet module have several methods, in this example I will make use of these:
read_until, read_all() and write() 

 Let's make a telnet script 

import getpass
import sys
import telnetlib

HOST = "hostname"

user = raw_input("Enter your remote account: ")

password = getpass.getpass()

tn = telnetlib.Telnet(HOST)

tn.read_until("login: ")

tn.write(user + "
")

if password:
    tn.read_until("Password: ")
    tn.write(password + "
")

tn.write("ls
")

tn.write("exit
")

print tn.read_all()

 At ActiveState you can find more Python scripts using the telnetlib, 
for example [this](https://code.activestate.com/recipes/52228/ "code") script.

For more information about using the Telnet client in Python, please see the 
[official documentation](https://docs.python.org/2/library/telnetlib.html "python"). 

foo = 10

bar = foo + 10

 x = 123 			# integer
x = 123L			# long integer
x = 3.14 			# double float
x = "hello" 			# string
x = [0,1,2] 			# list
x = (0,1,2) 			# tuple
x = open(‘hello.py’, ‘r’) 	# file

You can also assign a single value to several variables simultaneously multiple 
assignments.

Variable a,b and c are assigned to the same memory location,with the value of 1
a = b = c = 1 

length = 1.10
width  = 2.20
area   = length * width
print "The area is: " , area

This will print out: The area is:  2.42 

 Virtualenv is a tool to create isolated Python environments, it's perhaps the 
easiest way to configure a custom Python environment. 

Virtualenv allows you to add and modify Python modules without access to the
global installation. 

 The basic problem being addressed is one of dependencies and versions, and 
indirectly permissions. 

Imagine you have an application that needs version 1 of LibFoo, but another
application requires version 2\. 

How can you use both these applications? 

If you install everything into /usr/lib/python2.7/site-packages (or whatever your 
platform’s standard location is), it’s easy to end up in a situation where you 
unintentionally upgrade an application that shouldn’t be upgraded.

Or more generally, what if you want to install an application and leave it be? 

If an application works, any change in its libraries or the versions of those
libraries can break the application.

Also, what if you can’t install packages into the global site-packages directory? 

For instance, on a shared host.

In all these cases, virtualenv can help you. 

It creates an environment that has its own installation directories, that doesn’t
share libraries with other virtualenv environments 

 There are a few ways to install virtualenv on your machine. 

You can use either the source tarball, pip or by using easy_install. 

 $ sudo easy_install virtualenv

Searching for virtualenv
Reading http://pypi.python.org/simple/virtualenv/
Reading http://www.virtualenv.org
Reading http://virtualenv.openplans.org
Best match: virtualenv 1.8.2
Downloading http://pypi.python.org/packages/source/v/virtualenv/virtualenv-1.8.2.tar.gz... 
processing virtualenv-1.8.2.tar.gz
.....
....
Processing dependencies for virtualenv
Finished processing dependencies for virtualenv 

 Get the latest version from here: http://pypi.python.org/packages/source/v/virtualenv/
wget http://pypi.python.org/packages/source/v/virtualenv/virtualenv-1.8.tar.gz
tar xzvf virtualenv-1.8.tar.gz
python virtualenv-1.8/virtualenv.py $HOME/env 

 pip install virtualenv 

 To create virtual environments, you can use the virtualenv command. 

Create an environment called "foobar":
virtualenv foobar

Activate the environment by sourcing its activate script, which is located in the 
environment's bin/ directory:
source foobar/bin/activate

This will change your $PATH so its first entry is the virtualenv’s bin/ directory.

If you install a package in your virtual environment, you'll see that executable 
scripts are placed in foobar/bin/ and eggs in foobar/lib/python2.X/site-packages/
easy_install yolk

Yolk is a small command line tool which can, among other things, list the
currently installed Python packages on your system:
yolk -l

Virtualenv inherits packages from the system's default site-packages directory. 

This is especially useful when relying on certain packages being available,
so you don't have to go through installing them in every environment.

To leave an environment, simply run deactivate:
deactivate

If you execute he yolk command now, you will see that it won't work because the
package was installed only in your virtual environment. 

Once you reactivate your environment it will be available again. 

 I used different sources to find information for this article: 
the official virtualenv [website](http://www.virtualenv.org/en/latest/index.html "virtualenv latest"), from Chris Scott "[A Primer on virtualenv](http://iamzed.com/2009/05/07/a-primer-on-virtualenv/ "a primer on virtualenv")" and
from Arthur Koziel '[Working with virtualenv](http://www.arthurkoziel.com/2008/10/22/working-virtualenv/ "working-virtualenv")' 

 webbrowser.open_new(url)
    Open url in a new window of the default browser, if possible, otherwise,
    open url in the only browser window.

webbrowser.open_new_tab(url)
    Open url in a new page (“tab”) of the default browser, if possible, 
    otherwise equivalent to open_new(). 

import webbrowser
google = raw_input('Google search:')
webbrowser.open_new_tab('http://www.google.com/search?btnG=1&q=%s' % google) 

i = 0
while i < 10:
    print i
    i = i + 1

while True:
    print "Hello World"

 **import os**

Executing a shell command
**os.system()**    

Get the users environment 
**os.environ()**   

#Returns the current working directory.
**os.getcwd()**   

Return the real group id of the current process.
**os.getgid()**       

Return the current process’s user id.
**os.getuid()**    

Returns the real process ID of the current process.
**os.getpid()**     

Set the current numeric umask and return the previous umask.
**os.umask(mask)**   

Return information identifying the current operating system.
**os.uname()**     

Change the root directory of the current process to path.
**os.chroot(path)**   

Return a list of the entries in the directory given by path.
**os.listdir(path)** 

Create a directory named path with numeric mode mode.
**os.mkdir(path)**    

Recursive directory creation function.
**os.makedirs(path)**  

Remove (delete) the file path.
**os.remove(path)**    

Remove directories recursively.
**os.removedirs(path)** 

Rename the file or directory src to dst.
**os.rename(src, dst)**  

Remove (delete) the directory path.
**os.rmdir(path)** 

class Queue:
    def __init__(self):
        self.queueList=list()
        self.queueLength=0

def enQueue(self,data):
        self.queueList.append(data)
        self.queueLength=self.queueLength+1

def deQueue(self):
        try:
            if self.queueLength==0:
                raise Exception("Queue is Empty")
            else:
                temp=self.queueList.pop(0)
                self.queueLength=self.queueLength-1
                return temp
        except Exception as e:
            print(str(e))

def length(self):
        return self.queueLength

def isEmpty(self):
        if self.queueLength==0:
            return True
        else:
            return False

def front(self):
        try:
            if self.queueLength==0:
                raise Exception("Queue is Empty")
            else:
                temp=self.queueList[-1]
                return temp
        except Exception as e:
            print(str(e))

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
"""
Created on Sun Apr 25 20:15:56 2021

@author: aditya1117
"""

class Queue:
    def __init__(self):
        self.queueList=list()
        self.queueLength=0
    def enQueue(self,data):
        self.queueList.append(data)
        self.queueLength=self.queueLength+1
    def deQueue(self):
        try:
            if self.queueLength==0:
                raise Exception("Queue is Empty")
            else:
                temp=self.queueList.pop(0)
                self.queueLength=self.queueLength-1
                return temp
        except Exception as e:
            print(str(e))
    def isEmpty(self):
        if self.queueLength==0:
            return True
        else:
            return False
    def length(self):
        return self.queueLength
    def front(self):
        try:
            if self.queueLength==0:
                raise Exception("Queue is Empty")
            else:
                temp=self.queueList[-1]
                return temp
        except Exception as e:
            print(str(e))

import random

upper_limit = 1000
lower_limit = 0
print("The lower limit of the range is:", lower_limit)
print("The upper limit of the range is:", upper_limit)
number = random.randint(lower_limit, upper_limit)
print("The random number is:", number)

The lower limit of the range is: 0
The upper limit of the range is: 1000
The random number is: 739

import random

upper_limit = 1000
lower_limit = 0
print("The lower limit of the range is:", lower_limit)
print("The upper limit of the range is:", upper_limit)
range_of_nums = range(lower_limit, upper_limit)
number = random.choice(range_of_nums)
print("The random number is:", number)

The lower limit of the range is: 0
The upper limit of the range is: 1000
The random number is: 848

import random

upper_limit = 1000
lower_limit = 0
print("The lower limit of the range is:", lower_limit)
print("The upper limit of the range is:", upper_limit)
range_of_nums = range(lower_limit, upper_limit)
numbers = random.choices(range_of_nums, k=3)
print("The three random numbers are:", numbers)

The lower limit of the range is: 0
The upper limit of the range is: 1000
The three random numbers are: [105, 858, 971]

import numpy

upper_limit = 1000
lower_limit = 0
print("The lower limit of the range is:", lower_limit)
print("The upper limit of the range is:", upper_limit)
number = numpy.random.randint(lower_limit, upper_limit)
print("The random number is:", number)

The lower limit of the range is: 0
The upper limit of the range is: 1000
The random number is: 144

import numpy

upper_limit = 1000
lower_limit = 0
print("The lower limit of the range is:", lower_limit)
print("The upper limit of the range is:", upper_limit)
range_of_nums = range(lower_limit, upper_limit)
number = numpy.random.choice(range_of_nums)
print("The random number is:", number)

The lower limit of the range is: 0
The upper limit of the range is: 1000
The random number is: 264

import csv

myFile = open('Demo.csv', 'r')
reader = csv.reader(myFile)
myList = []
for record in reader:
    myList.append(record)
print("The list of lists is:")
print(myList)

The list of lists is:
[['Roll', 'Name', 'Language'], ['1', 'Aditya', 'Python'], ['2', 'Sam', ' Java'], ['3', ' Chris', ' C++']]

import csv

myFile = open('Demo.csv', 'r')
reader = csv.reader(myFile)
print("The header is:")
print(next(reader))
myList = []
for record in reader:
    myList.append(record)
print("The list of lists is:")
print(myList) 

The header is:
['Roll', 'Name', 'Language']
The list of lists is:
[['1', 'Aditya', 'Python'], ['2', 'Sam', ' Java'], ['3', ' Chris', ' C++']]

import csv

myFile = open('Demo.csv', 'r')
reader = csv.reader(myFile)
myList = list(reader)
print("The list of lists is:")
print(myList)

The list of lists is:
[['Roll', 'Name', 'Language'], ['1', 'Aditya', 'Python'], ['2', 'Sam', ' Java'], ['3', ' Chris', ' C++']]

import csv

myFile = open('Demo.csv', 'r')
reader = csv.reader(myFile)
print("The header is:")
print(next(reader))
myList = list(reader)
print("The list of lists is:")
print(myList) 

The header is:
['Roll', 'Name', 'Language']
The list of lists is:
[['1', 'Aditya', 'Python'], ['2', 'Sam', ' Java'], ['3', ' Chris', ' C++']] 

import csv

myFile = open('Demo.csv', 'r')
reader = csv.DictReader(myFile)
myList = list()
for dictionary in reader:
    myList.append(dictionary)
print("The list of dictionaries is:")
print(myList)

The list of dictionaries is:
[{'Roll': '1', 'Name': 'Aditya', 'Language': 'Python'}, {'Roll': '2', 'Name': 'Sam', 'Language': ' Java'}, {'Roll': '3', 'Name': ' Chris', 'Language': ' C++'}] 

import csv

myFile = open('Demo.csv', 'r')
reader = csv.DictReader(myFile)
myList = list(reader)
print("The list of dictionaries is:")
print(myList) 

The list of dictionaries is:
[{'Roll': '1', 'Name': 'Aditya', 'Language': 'Python'}, {'Roll': '2', 'Name': 'Sam', 'Language': ' Java'}, {'Roll': '3', 'Name': ' Chris', 'Language': ' C++'}]

myFile = open('sample.txt', 'r')
print("The content of the file is:")
while True:
    text = myFile.readline()
    if text == "":
        break
    print(text, end="")
myFile.close()

The content of the file is:
I am a sample text file.
I was created by Aditya.
You are reading me at Pythonforbeginners.com.

myFile = open('sample.txt', 'r')
print("The content of the file is:")
lines = myFile.readlines()
for text in lines:
    print(text, end="")
myFile.close()

The content of the file is:
I am a sample text file.
I was created by Aditya.
You are reading me at Pythonforbeginners.com.

import pandas as pd
import numpy as np
df=pd.read_csv("demo_file.csv")
print("The dataframe is:")
print(df)

The dataframe is:
     Name  Roll    Language
0  Aditya     1      Python
1     Sam     2        Java
2   Chris     3         C++
3    Joel     4  TypeScript

import pandas as pd
import numpy as np
df=pd.read_csv("demo_file.csv")
print("The dataframe is:")
print(df)
specific_column=df["Name"]
print("The column is:")
print(specific_column)

The dataframe is:
     Name  Roll    Language
0  Aditya     1      Python
1     Sam     2        Java
2   Chris     3         C++
3    Joel     4  TypeScript
The column is:
0    Aditya
1       Sam
2     Chris
3      Joel
Name: Name, dtype: object

import pandas as pd
import numpy as np
df=pd.read_csv("demo_file.csv")
print("The dataframe is:")
print(df)
specific_columns=df[["Name","Roll"]]
print("The column are:")
print(specific_columns)

The dataframe is:
     Name  Roll    Language
0  Aditya     1      Python
1     Sam     2        Java
2   Chris     3         C++
3    Joel     4  TypeScript
The column are:
     Name  Roll
0  Aditya     1
1     Sam     2
2   Chris     3
3    Joel     4

import pandas as pd
import numpy as np
df=pd.read_csv("demo_file.csv",usecols=["Name"])
print("The dataframe is:")
print(df)

The dataframe is:
     Name
0  Aditya
1     Sam
2   Chris
3    Joel

# read.py
# loading a file with open()
myfile = open(“emily_dickinson.txt”)

# reading each line of the file and printing to the console
for line in myfile:
	print(line)

>python read.py

# open the file in write mode
myfile = open(“sample.txt”,’w’)

myfile.write(“Hello from Python!”)

>python write.py

# open the file in write mode
myfile = open(“sample.txt”,’w’)

myfile.writelines(“Hello World!”,”We’re learning Python!”)

# close the file
myfile.close()

# open the file in write mode
myfile = open("poem.txt", 'w')

line1 = "Roses are red.\n"
line2 = "Violets are blue.\n"
line3 = "Python is great.\n"
line4 = "And so are you.\n"

myfile.write(line1 + line2 + line3 + line4)

# binary files need a special argument: ‘b’
binary_file = open(“song_data.mp3”,’rb’)
song_data = binary_file.read()

# close the file
binary_file.close()

# open a file
myfile = open(“poem.txt”)
# an array to store the contents of the file
lines = []
For line in myfile:
	lines.append(line)

# close the file
myfile.close()

For line in liens:
	print(line)

pip install Pillow

From PIL import Image

# tell Pillow to open the image file
img = Image.open(“your_image_file.jpg”)
img.show()
img.close()

***with open(“filename”) as file:* **

***with open(“poem.txt”) as file: * **
***data = file.read()* **
***do something with data* **

**w*ith open(“poem.txt”) as f:* **
***for line in f:* **
***print line,* **

***with* *open(**“**hello.text**”, “r”) as f:***
***data =* *f.readlines**()***

***for line in data:***
***words =* *line.split**()***
***print words***

***[“hello”, “world”, “how”, “are”, “you”, “today?”]***
***[“today”, “is”, “Saturday”]***

龙哥盟

掠夺·扩张·投机·博弈

PythonForBeginners 中文系列教程（三）

Python 中列表中最小元素的索引

使用 for 循环的列表中最小元素的索引

Python 中的 len()函数

Python 中的 range()函数

使用 min()函数和 Index()方法对列表中的最小元素进行索引

Python 中的 min()函数

Python 中的 index()方法

使用 Numpy 模块的列表中最小元素的索引

多次出现时列表中最小元素的索引

使用 min()函数和 For 循环的列表中最小元素的索引

使用 min()函数和列表理解的列表中最小元素的索引

使用 min()函数和 enumerate()函数的列表中最小元素的索引

Python 中的 enumerate()函数

结论

Python 中的 IndexError

Python 中什么是 IndexError？

Python 中如何避免 IndexError？

使用 If-Else 块抢占 IndexError

使用 Try-Except 块处理 IndexError

结论

Python 中的内部连接数据帧

什么是内部联接操作？

使用 merge()方法内部连接两个数据帧

使用 Join()方法内部连接两个数据帧

结论

在 Python 中的排序列表中插入元素

如何在排序列表中插入元素？

使用切片

使用 insert()方法

使用等分模块在排序列表中插入元素

结论

用 Python 在数据帧中插入新列

在 Python 中通过索引将新列插入数据帧

使用 assign()方法将新列插入数据帧

使用 Insert()方法将新列插入数据帧

结论

Python 中列表的交集

如何在 python 中执行列表的交集？

python 中使用 For 循环的两个列表的交集

python 中使用集合的两个列表的交集

结论

Python 中的 cmath 模块简介

计算复数的相位

复数的极坐标

cmath 模块中的常数

cmath 模块中的三角函数

cmath 模中的双曲函数

cmath 模块中的对数函数

cmath 模块中的幂函数

结论

Python 中的 Deque 模块介绍

如何使用 Python 中的 deque 模块？

如何在一个队列中插入元素？

如何在 Python 中删除 deque 中的元素？

统计特定元素在队列中的出现次数

反转队列中的元素

搜索队列中的元素

如何在 Python 中旋转一个 deque？

结论

IPython 简介

概观

IPython 是什么？

为什么选择 IPython？

安装 IPython？

启动 IPython

从文件运行 Python 代码

制表符结束

宏指令

使用 Python 调试器(pdb)

轮廓

启动文件

IPython 中的命令

lxmagic

帮助命令

更多命令

系统外壳访问

使用熊猫数据框的字典列表。`DataFrame`()