• python 基本语法


    一、Hello World

      python下的Hello World写法:

     

    1 #!/usr/bin/env python
    2 # _*_ coding: UTF-8 _*_
    3 # Author:taoke
    4 print("Hello world!!!")
    [#!usr/bin/env python] 解释:
    寻找linux系统下的python环境变量
    [# _*_ coding: UTF-8 _*_] 解释:
    当前文件使用UTF-8 编码
    [# Author:taoke] 解释:
    没错,就是我>_<

    二、变量
      变量定义的规则:
      1、变量名只能够是数字、字母、下划线的任意组合
      2、变量名的第一个字符不能够是数字
      3、以下关键字不能够作为变量名
        [and,as,assert,break,class,continue,def,del,elif,else,
         except,exec,finally,for,from,global,if,import,in,is,lambda,
         not,or,pass,print,raise,return,try,while,with,yield]
      (python中没有常量的概念,个人定义把变量名全大写的变量作为常量来使用)


    三、编码
      ASCII编码 255 1bytes
        -->1980 GB2312 2bytes
        -->1995 GBK1.0 2w+
        -->2000 GB18030 27xxx
        -->1994 unicode 2bytes (万国码)
        -->UTF8 en(ascii):1bytes
             ch:3bytes


    四、注释
    1、# 注释内容
    2、‘‘‘
       注释内容
       ’’’

    五、用户交互程序(input和格式化输出)
    字符串拼接尽量不使用,
    用以下三种格式化输出的方式:
      
     1 #!/usr/bin/env python
     2 # _*_ coding: UTF-8 _*_
     3 # Author:taoke
     4 
     5 name = input("name:")
     6 job = input("job:")
     7 salary = input("salary:")
     8 age = int(input("age:"))
     9 print(type(age),type(str(age)))
    10 outstr1 = """
    11 ------info %s-------
    12 name:%s
    13 job:%s
    14 salary:%s
    15 age:%d
    16 """%(name,name,job,salary,age)
    17 outstr2 = """
    18 ------info {_name}-------
    19 name:{_name}
    20 job:{_job}
    21 salary:{_salary}
    22 age:{_age}
    23 """.format(_name = name,
    24             _job = job,
    25             _salary = salary,
    26             _age = age)
    27 outstr3 = """
    28 ------info {0}-------
    29 name:{0}
    30 job:{1}
    31 salary:{2}
    32 age:{3}
    33 """.format( name,
    34             job,
    35             salary,
    36             age)
    37 
    38 print(outstr3)
    六、猜年纪的游戏(while 和 if)
     1 #!/usr/bin/env python
     2 # _*_ coding: UTF-8 _*_
     3 # Author:taoke
     4 reallyAge = 43
     5 guessage = 0
     6 while guessage != reallyAge:
     7     guessage = int(input("please input guess age:"))
     8     if guessage<reallyAge:
     9         print("小了")
    10     elif guessage>reallyAge:
    11         print("大了")
    12 else:
    13     print("猜对了")

    七、作业

    1、编写登录接口

      1) 输入用户名密码

      2)登录成功后显示欢迎信息

      3)输错三次后锁定(即:输出用户已被锁定)

     1 #!/usr/bin/env python
     2 # _*_ coding: UTF-8 _*_
     3 # Author:taoke
     4 
     5 username = 'huangye'
     6 password = '123456'
     7 flag=0
     8 count = 0
     9 while True:
    10     inputname = input("用户名:")
    11     inputpassword = input("密码:")
    12     if inputname == username:
    13         if count<3:
    14             if inputpassword == password:
    15                 print("欢迎{_username}使用".format(_username = inputname))
    16                 break
    17             else:
    18                 count+=1
    19                 print("用户名或密码错误")
    20         else:
    21             print("用户已被锁定")
    22     else:
    23          print("用户名或密码错误")

     2、编写一个多级菜单程序

    1) 三级菜单

    2)可一次选择进入各级子菜单

     1 #!/usr/bin/env python
     2 # _*_ coding: UTF-8 _*_
     3 # Author:taoke
     4 #三级菜单
     5 dic_ = { "tap_main":("tap1","tap2","tap3"),
     6         "tap1":("tap1_1","tap1_2","tap1_3"),
     7         "tap2":("tap2_1","tap2_2","tap3_3"),
     8         "tap3":("tap3_1","tap3_2","tap3_3"),
     9         "tap1_1":('tap1_1 msg1','tap1_1 msg2','tap1_1 msg3'),
    10         "tap1_2":('tap1_2 msg1','tap1_2 msg2','tap1_2 msg3'),
    11         "tap1_3":('tap1_3 msg1','tap1_3 msg2','tap1_3 msg3'),
    12         "tap2_1":('tap2_1 msg1','tap2_1 msg2','tap2_1 msg3'),
    13         "tap2_2":('tap2_2 msg1','tap2_2 msg2','tap2_2 msg3'),
    14         "tap2_3":('tap2_3 msg1','tap2_3 msg2','tap3_3 msg3'),
    15         "tap3_1":('tap3_1 msg1','tap3_1 msg2','tap3_1 msg3'),
    16         "tap3_2":('tap3_2 msg1','tap3_2 msg2','tap3_2 msg3'),
    17         "tap3_3":('tap3_3 msg1','tap3_3 msg2','tap3_3 msg3'),
    18        }
    19 
    20 menuName = "tap_main"
    21 curmenu = "tap_main"
    22 print(dic_[curmenu])
    23 while True:
    24     menuName = input("需要访问的菜单名:")
    25     if menuName == 'b':
    26         #输出上一级菜单
    27         if curmenu == "tap_main":
    28             print("输入错误")
    29         elif curmenu == "tap1" or curmenu == "tap2" or curmenu == "tap3":
    30             curmenu = "tap_main"
    31         elif curmenu == "tap1_1" or curmenu == "tap1_2" or curmenu == "tap1_3":
    32             curmenu = "tap1"
    33         elif curmenu == "tap2_1" or curmenu == "tap2_2" or curmenu == "tap2_3":
    34             curmenu = "tap2"
    35         elif curmenu == "tap3_1" or curmenu == "tap3_2" or curmenu == "tap3_3":
    36             curmenu = "tap3"
    37     elif menuName == 'q':
    38         break
    39     else:
    40         if menuName in dic_.keys():
    41             curmenu = menuName
    42         else:
    43             print("输入错误")
    44     print(dic_[curmenu])
    45 
    46 print("程序结束")






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  • 原文地址:https://www.cnblogs.com/taoke2016/p/7466011.html
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