多级菜单

#多级菜单city = {‘湖南‘:{‘长沙‘:{‘解放路‘,‘芙蓉路‘},‘衡阳‘:{‘石鼓区‘,‘珠晖区‘}},        ‘北京‘: {‘北京市‘: {‘1号‘, ‘2号‘}, ‘郊区‘: {‘3号‘, ‘4号‘}}}print(‘输入b返回上一层‘)back = ‘b‘while True:    for i in city:        print(i)

choice = input(‘请输入省份：‘).strip()    if choice in city:        while True:            for j in city[choice]:                print(j)

choice2 = input(‘请输入城市‘).strip()

if choice2 == back:                break            if choice2 in city[choice]: #错误点 不能用索引判断在一个序列中

while True:                    for k in city[choice][choice2]:                        print(k)

choice3 = input(‘输入b，返回上一层‘).strip()

if choice3 ==  back:                        break                    else:                        pass            else:                print(‘错误，请重新输入‘)                continue    else:        print(‘请重新输入‘)        continue1.纯循环语句写的2.不能用索引判断是否在一个字典中