Python学习之自动化开发-DAY1作业-三级菜单

简单按照老师的思路做了一个三级菜单，感觉最有意思的是用了三个循环点，i=1,i=2,i=3,然后程序可以跳转到相应的循环点去，程序如下：

 1 #!/usr/bin/env python3
 2 #-*_coding:utf-8_*_
 3 city_overview={'peking':{'peking':['estern','western']},'shanghai':{'shanghai':['pudong','hongkou','fengxian']}}
 4 
 5 print('now you can choose the city:',city_overview.keys())
 6 i=1
 7 while i==1:
 8     prov=input('Please input input a prov(press "b" to go back):')
 9     if prov in city_overview.keys():
10         i = 2
11         while i==2:
12             for i in city_overview[prov].keys():
13                 print(i)
14             city=input('please choose a city(press "b" to go back):')
15             if city in city_overview[prov].keys():
16                 i=3
17                 while i==3:
18                     for i in city_overview[prov][city]:
19                         print(i)
20                     country=input('Please input the country(press "b" to go back):')
21                     if country in city_overview[prov][city]:
22                         print(prov,city,country)
23                         break
24                     elif country=='b' or country=='B':
25                         i=2
26                         break
27                     else:
28                         print('invalid country input,please try again')
29             elif city == 'b' or city == 'B':
30                 i = 1
31                 break
32             else:
33                 print('invalid city input,please try again.')
34     elif prov=='b' or prov=='Q':
35         break
36     else:
37         print('invalid province input,please try again.')