Python学习笔记

https://www.bilibili.com/video/av75855831?from=search&seid=14589661103677033438

Mosh Hamedani的教程

input：
    输入，以及类型转换
    birth_year = int(input(‘Birth year: ‘))
    input("").lower

strings：
    字符串的定位：
        course = ‘Python for Beginners’

        course[0] # returns the first character

        course[1] # returns the second character

        course[-1] # returns the first character from the end 
 course[-2] # returns the second character from the end
        course[1:5] 连续

    字符串的格式化输出
        name = ‘Mosh’
        message = f’Hi, my name is {name}’  格式化输出

    字符串乘法：
        就是复制n份，print("abc"*2), 即输出abcabc

    字符串的函数，大小写，查找等
        message.upper()
        message.lower()
        message.title(）# to capitalize the first letter of every word
        message.find(‘p’) # returns the index of the first occurrence of p 
(or -1 if not found)
        message.replace(‘p’, ‘q’)

    in,用于检查是否包含于该字符串中：
        test="xxabcaa"
        print("abc" in test)
        >>True

    打印
        打印多行字符串：
        print("""
        ssxx
        xxxx
        xxxx """）

算法
    +，-，*，/, **平方
    x+=10等效于x=x+10

    使用数学函数：
        import math
        x = math.ceil(2.9), floor,abs,,,,

if语句
    if, elif, else, and, or
    if is_hot:

        print(“hot day”)

    elif is_cold:

        print(“cold day”)

    else: 

        print(“beautiful day”)

while语句
    while, break, else
    i = 1
    while i <= 3:
        i = i + 1
        if xxx:
            print ("greate")
            break
    else:



for语句
    可嵌套，
    for item in 'Python':
        print(item)

    for item in range(10):   0~10,
    range(5,10,2) 5~10,step=2

    不换行打印--  print("",end="")

list
    numbers = [1, 2, 3, 4, 5]

    numbers[0]
    numbers[1]

    numbers.append(6)   直接加个
    numbers.insert(0, 6)  位置，插入值
    numbers.remove(6)
    numbers.pop()
    numbers.clear()     不需要值
    numbers.index(8)
    numbers.sort()
    numbers.reverse()
    numbers.copy()

    numbers = [ 2,3,4,5,6 ]
    numbers.append(66)
    print(numbers)  #[2, 3, 4, 5, 6, 66]
    numbers2 = numbers.copy()
    print(numbers2) #[2, 3, 4, 5, 6, 66]

    names = ['Jone','Bob','Mosh','Sara','Mark']
    names[0]
    names[2:]

    numbers = [
            [ 1, 2, 3 ],
            [ 4, 5, 6 ],
            [ 7, 8, 9 ],
            [ 4, 7, 9 ],
    ]
    print (numburs[1][1])  >>5
    for row in numbers:
        for item in row:
            print(item)

    list的unpackting，解压
    coordinates  = (1,2,3)
    x = coordinates[0]
    y = coordinates[1]
    z = coordinates[2]
    a,b,c = coordinates
    print(f"{x},{y},{z}")
    print(f"{a},{b},{c}")


dictionary
    举例：
    customers = {
        "name" : "Jack",
        "age" : 30,
        "is_verified" : True
    }
    print(customers)
    print(customers["name"])
    print(customers["name"][0])
    print(customers["age"])
    print(customers.get("bith","default value is here"))
    customers["bith"] = "1989"
    print(customers.get("bith","default value is here"))
    >> {'name': 'Jack', 'age': 30, 'is_verified': True}
    >> Jack
    >> J
    >> 30
    >> default value is here
    >> 1989

   字典的查询使用：
   digits = {
    "1" : "one",
    "2" : "two",
    "3" : "three"
    }
    phone_num = input("what's your phone num？ ")
    for char in phone_num:
        output = digits.get(char,"*")
        print(output,end=" ")
    >> what's your phone num？ 1235782
    >> one two three * * * two

    messages = input(">")
    words=messages.split(' ')
    emojis = {
        ":)" : "😀",
        ":(" : "😭"
    }
    for item in words:
        print(emojis.get(item,item),end=" ")
    >> >good morning :(
    >> good morning 😭

异常处理
    try:
        age = int(input("age: "))
        print(f"age: {age}")
    except ValueError:
        print("Please input valid number")

class
    class Point:
        def __init__(self, x_input, y_input):
            self.x = x_input  
            self.y = y_input

        def move(self):
            print("xxxx:")

        def draw(self):
            print("draw")

    point = Point(100, 20)
    print(point.x)
    point.x = 111
    print(point.x)

    class Person:
        def __init__(self, name_input):
            self.name = name_input

        def print_name(self):
            words = self.name.split(" ")
            output = ""
            for item in words:
                output += item + ","
            print(f"Hello, {output}")

    person = Person("shi wen ming")
    person.print_name()
    >>>Hello, shi,wen,ming,