三级菜单_简易方式

#---author:Administrator---
#---DATE:2019/4/15---
#---TIME:11:24---

menu = {
    '北京':{
        '朝阳区':{
            '国贸':{
                '大裤衩':{},
                'CBD':{},
                '购物':{},
            },
            '双井':{},
            '劲松':{},
        },
        '海淀区':{},
        '昌平区':{},
    },
    '上海':{},
    '山西':{},
}
current_layer = menu
parent_layers = []

while True:
    for key in current_layer:
        print(key)
    chooice = input('>>>:').strip()
    if len(chooice) == 0:continue
    if chooice in current_layer:
        parent_layers.append(current_layer)
        current_layer = current_layer[chooice]
    elif chooice == 'b':
        if parent_layers:
            current_layer = parent_layers.pop()
    elif chooice == 'q':
        exit()

    else:
        print('非法输入,请重新输入:')