标签：tag src erro put 注意 pre 简单的 cmd tin
1. while循环：条件循环
I: 基本语法
while 条件:
代码1
代码2
代码3
...
示范:
name_of_bk = ‘egon‘
pwd_of_bk = ‘123‘
tag = True#定义条件为真
while tag:
inp_name = input(‘your name>>: ‘)#输入姓名
inp_pwd = input(‘your password>>: ‘)#输入密码
if inp_name == name_of_bk and inp_pwd == pwd_of_bk: #判断是否姓名,密码一致
print(‘login successful‘)
tag = False#改变条件,终止循环
else:
print(‘username or password error‘)
print(‘other code...‘)
2: while+break:break代表结束本层循环
示范：
while True:
print(1)
break
print(2)
print(3)
name_of_bk = ‘egon‘ pwd_of_bk = ‘123‘ while True: inp_name = input(‘your name>>: ‘) inp_pwd = input(‘your password>>: ‘) if inp_name == name_of_bk and inp_pwd == pwd_of_bk: print(‘login successful‘) break else: print(‘username or password error‘) print(‘other code......‘)
3: while + continue: continue代表结束本次循环，直接进入下一次
示范
count=1 while count < 6: if count == 3: count+=1 continue print(count) count+=1
4:while + else
else的子代块只有在while循环没有被break打断的情况下才会执行
count=0 while True: if count == 10: break print(count) count+=1 else: print("")
注意:
两个经典代码:
简单购物车
简单的购物程序: name_of_bk=‘egon‘ pwd_of_bk=‘123‘ count=0 tag=True while tag: if count == 3: print(‘输错的次数过多。。。‘) break inp_name=input(‘your name>>: ‘) inp_pwd=input(‘your password>>: ‘) if inp_name == name_of_bk and inp_pwd == pwd_of_bk: print(‘login successful‘) while tag: print(""" 0 退出 1 购物 2 支付 3 查看购物 """) cmd=input(‘>>>: ‘) if cmd == ‘0‘: tag=False continue if cmd == ‘1‘: print(‘购物。。。。。。。‘) elif cmd == ‘2‘: print(‘支付。。。。。‘) elif cmd == ‘3‘: print(‘查看购物车‘) else: print(‘输入错误的指令‘) else: print(‘username or password error‘) count+=1 #count=3 输错3次
输错三次退出
1 输错三次退出 2 name_of_bk = ‘egon‘ 3 pwd_of_bk = ‘123‘ 4 5 count = 0 6 while True: 7 if count == 3: 8 print(‘输错的次数过多。。。‘) 9 break 10 inp_name = input(‘your name>>: ‘) 11 inp_pwd = input(‘your password>>: ‘) 12 if inp_name == name_of_bk and inp_pwd == pwd_of_bk: 13 print(‘login successful‘) 14 break 15 else: 16 print(‘username or password error‘) 17 count += 1 # count=3 输错3次
句型:循环嵌套
tag=True while tag: ...... while tag: ........ while tag: tag=False
标签：tag src erro put 注意 pre 简单的 cmd tin
原文地址：https://www.cnblogs.com/martin-wang/p/10001823.html
