python基础知识一

编译的概念

把名文代码执行前，先转成二进制，再执行， 这个过程就叫编译

sh test.sh #shell 程序的解释器

编译型与解释型

编译型语言包括：c、c++、go 等

特点：运行效率高 依赖编译平台 linux 操作系统 跟cpu交互的接口，与windows不是完全一样，不能跨平台 ，开发效率低

linux: print_to_console

windows: print_to_screen

解释型语言包括：shell、python、php、ruby 等

特点：运行效率低 跨平台，sh 解释器 负责跟不同的平台沟通，开发效率高，解释型的语言一般不需要关注硬件底层，学习成本低

变量

变量说直白一点就相当于一个容器，用来存储数据到内存中。

变量格式：

驼峰体：TrafficCost = windows 程序开发人员喜欢用 c#

官方推荐：traffic_cost = python

trafficcost age_of_oldboy = 56

ageofoldboy = 56

AGE_OF_OLDBOY = 56 #常量 不变的量

“ctrl + ?”  ---->  注释选中的 流程控制

if ...  elif ... else 判断

if ...判断条件

elif ...接着上面的继续判断

……

elif ...接着上面的继续判断

else ...上面的条件都不满足，则执行这一条内容

判断xxx的数据类型

print(type(xxx))

4 = integer = int 整数，整型

4 = string = str 字符串

a = string

改变xxx的类型：

int(“xxx”) ---> 转变为整数、整型 （int）

str(xxx) ---> 转变为字符串 （str）

同一类型的数据类型可以 相互操作， 整数+ 整数，

注意：字符串不能与整型进行计算、比较。

实操一

猜年龄 ， 可以让用户最多猜三次

age = 34
for i in range(3):
    age_guess = int(input('input your guess:'))
    if age_guess > age:
        print("try smaller...")
    elif age_guess < age:
        print("try bigger...")
    else:
        print("Congratulations you guessed it")
        break
else:
    print("Input too many times")

或

age = 34
count = 0
while count<3:
    age_guess = int(input("input your guess:"))
    if age_guess > age:
        print("try smaller...")
    elif age_guess < age:
        print("try bigger...")
    else:
        print("Congratulations you guessed it")
        break
    count += 1
else:
    print("Input too many times")

实操二

猜年龄 ，每隔3次，问他一下，还想不想继续玩，y,n

age = 34
count = 0
while True:
    if count < 3:
        age_guess = int(input("please input your age:"))
        if age_guess > age:
            print("try smaller...")
        elif age_guess < age:
            print("try bigger...")
        else :
            print("Congratulations you guessed it")
            break
        count += 1
    elif count == 3:
        select_ge = "Continue to play don't play?(Y/N)"
        chioce = input("Continue to play don't play?Y/N")
        if chioce == "y" or chioce == "Y":
            print("Keep on talking")
            count = 0
        elif chioce == "n" or chioce == "N":
            print("Do not want to play")
            break　

或

age = 34
while True:
    for i in range( 3 ):
        age_guess = int(input('input your guess:'))
        if age_guess > age:
            print("try smaller...")
        elif age_guess < age:
            print("try bigger...")
        elif age_guess == age:
            print("Congratulations you guessed it")
            exit()
    else :
        chioce = input("Continue to play don't play?Y/N")
        if chioce == "y" or chioce == "Y":
            print("Keep on talking")
        elif chioce == "n" or chioce == "N":
            print("Do not want to play")
            exit()　

实操3

编写登陆接口
输入用户名密码
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输错三次后锁定