The first section of Python learning notes

First, HelloWorld

#！ /usr/bin/env python

#-*-Coding:utf-8-*-

Print ("helloworld!")


Second, user interaction

#!/usr/bin/env python #_*_coding:utf-8_*_ name  =  input ( "What is your name?" ) print ( "Hello "  name )

When entering a password, if you want to be invisible, you need to take advantage of the Getpass method in the Getpass module, namely: importgetpass

# 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, but can be performed in a Linux environmentThird, string formatted output name  = "emily" print "i am %s " % name   #输出: i am emily PS: string is%s; integer%d; floating-point number%f Iv. expression 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!")Five. While statement

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 ")

VI. For statement

For I in range (10):
        Print ('------', i)
        For j in Range (10):
             Print (j)
             If j>5:
                 Break

The first section of Python learning notes