Python编程基础

#以下是Python编程基础知识

import sys

from sys import argv,path #导入特定成员

print('path:',path)

print('============Python import mode===========================')

print('命令行参数为：')

for i in sys.argv:

    print(i)

print('\n python 路径为',sys.path)

count =100

miles =1000.0

name ="runoob"

a,b,c = 1,2,"runoob"

print(100)

print(miles)

print(name)

print(a)

print(b)

print(c)

'''

数据标准

'''

"""

注释

"""

#标准数据类型#

#列表

list = ["abc",1,1.1]

#元组

tuple =("abcd",786,2.23,"runoob",70.2)

#集合  进行成员关系测试和删除重复元素  {}不能创建空集合

sites = {'google','taobao','jD',123.1,'fb',123}

if 123.1 in sites:

   print("Runoob在集合中")

else:

   print("Runoob不在集合中")

     

a = set('aaaadddgd')

b = set('aabbtt')

print(a-b)

print(a|b)

print(a&b)

print(a^b)#a 与 b中不同时存在的元素

#字典  键值对

dict = {}

dict['one'] = "1-菜鸟教程"

dict[2] = "222222"

tiny_dict = {'name':'runoob','code':1,'site':'www.runoob.com'}

print(tiny_dict)

print(tiny_dict.keys())

print(tiny_dict.values())

#列表推导式

#[表达式 for 变量 in 列表] 或者 [表达式]

names = ['Bob','Tom','alice','Jerry','Wendy','Smith']

new_names = [name.upper()for name in names if len(name)>3]

print(new_names)

#字典推导式{ key_expr: value_expr for value in collection }或{ key_expr: value_expr for value in collection if condition }

listdemo = ['Google','Runoob', 'Taobao']

# 将列表中各字符串值为键，各字符串的长度为值，组成键值对

newdict = {key:len(key) for key in listdemo}

print(newdict)

#集合推导式

# { expression for item in Sequence }

# 或

# { expression for item in Sequence if conditional }

a = {x for x in 'abracadabra' if x not in 'abc'}

#元组推导式

# (expression for item in Sequence )

# 或

# (expression for item in Sequence if conditional )

a = (x for x in range(1,10))

###############类

class MyClass:

    i = 12345

    def f(self):

        return 'hello world'

#实例化

x = MyClass()

class Complex:

    def __init__(self, realpart,imagpart):

        self.r = realpart

        self.i = imagpart

x = Complex(3.0,-4.6)

#类定义

class people:

    #定义基本属性

    name = ''

    age = 0

    #私有属性类外无法访问

    __weight = 0

    #定义构造方法

    def __init__(self,n,a,w):

        self.name = n

        self.age = a

        self.__weight = w

    def speak(self):

        print("%s say : I %d years" %(self.name,self.age))

#实例化

pp = people("zsj",4,100)

pp.speak()

#继承

class student(people):

    grade = ''

    #调用父类的构函

    def __init__(self,n,a,w,g):

        people.__init__(self,n,a,w)

        self.grade = g

        #覆写父类的方法

    def speak(self):

            print("%s 说: 我 %d 岁了，我在读 %d 年级"%(self.name,self.age,self.grade))

s = student('ken',10,60,3)

s.speak()

       

   

   

############################

def fibonacci(n): # 生成器函数 - 斐波那契

    a, b, counter = 0, 1, 0

    while True:

        if (counter > n):

            return

        yield a

        a, b = b, a + b

        counter += 1

f = fibonacci(10) # f 是一个迭代器，由生成器返回生成

 

while True:

    try:

        print (next(f), end=" ")

    except StopIteration:

        sys.exit()

#if语句

a = 'hello'

if('h' in a):

    print("h is in a")

else:

    print("h is not in a")

   

if('H' not in a):

    print("H is not in a")

else:

    print("H is in a")

   

#while语句

a,b = 0,1

while b < 10:

    print(b)

    a,b = b,a+b

else:

    print (b, " 大于或等于 10")

   

a,b = 0,1

while b < 10:

    print(b,end=',')

    a,b = b,a+b

   

#迭代器

list =[1,2,3,4]

it = iter(list)

for x in it:

    print(x,end= ' ')

 

#异常处理机制  

while True:

    try:

        print(next(it))

    except StopIteration:

        sys.exit()