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：

#!/usr/bin/env python3
#-*_coding:utf-8_*_
city_overview={'peking':{'peking':['estern','western']},'shanghai':{'shanghai':['pudong','hongkou','fengxian']}}

print('now you can choose the city:',city_overview.keys())
i=1
while i==1:
    prov=input('Please input input a prov(press "b" to go back):')
    if prov in city_overview.keys():
        i = 2
        while i==2:
            for i in city_overview[prov].keys():
                print(i)
            city=input('please choose a city(press "b" to go back):')
            if city in city_overview[prov].keys():
                i=3
                while i==3:
                    for i in city_overview[prov][city]:
                        print(i)
                    country=input('Please input the country(press "b" to go back):')
                    if country in city_overview[prov][city]:
                        print(prov,city,country)
                        break
                    elif country=='b' or country=='B':
                        i=2
                        break
                    else:
                        print('invalid country input,please try again')
            elif city == 'b' or city == 'B':
                i = 1
                break
            else:
                print('invalid city input,please try again.')
    elif prov=='b' or prov=='Q':
        break
    else:
        print('invalid province input,please try again.')