python学习笔记第一节

一、HelloWorld

#！/usr/bin/env python

#-*- coding:utf-8 -*-

print("HelloWorld!")


二、用户交互

#!/usr/bin/env python

#_*_coding:utf-8_*_

name = input("What is your name?")

print("Hello " name )

输入密码时，如果想要不可见，需要利用getpass 模块中的 getpass方法，即：import getpass

# 将用户输入的内容赋值给 name 变量

pwd = getpass.getpass("请输入密码：")

  

# 打印输入的内容

print(pwd)

#!/usr/bin/env python

# -*- coding: utf-8 -*-

username = input("username:")

password =  getpass.getpass("password:")

print("username,password")

#在pycharm中会执行不了，但可在Linux环境下执行

三、字符串格式化输出

name = "emily"

print "i am %s " % name

  

#输出: i am emily

PS: 字符串是 %s;整数 %d;浮点数%f

四、表达式 if......else

#!/usr/bin/env python　　

# -*- coding: utf-8 -*-

_username = 'emily'

_password = 'abc123'

username = input("username:")
password = input("password:")

if _username == username and _password == password:
　　print("welcome user {name} login...")
else:
　　print("invalid username or password!")

五、while语句

a = 30
count = 0
while count <3:
    b = int(input("a:"))
    if a == b:
        print("yes")
        break
    elif a>b:
        print("small")
    else:
        print("big")
    count +=1
else:
    print ("you have tried too many times..fuck off")

六、for语句

for i in range(10):
        print('------',i)
        for j in range(10):
             print(j)
             if j>5:
                 break