【Rollo的Python之路】Python:三级菜单练习 升级版

menu = {
    "深圳":{
        "罗湖":{
            "罗湖火车站": {},
            "东门": {},
            "国贸": {},
            "布心": {},
        },
        "福田":{
            "香蜜湖": {},
            "华强北": {},
            "华强南": {},
            "市民中心": {},
        },
        "南山": {
            "南山中心城": {},
            "南头关": {},
            "华侨城": {},
        },
        "宝安": {
            "宝安中心": {},
            "西乡": {},
            "松岗": {},
        },
        "龙岗": {
            "龙岗中心城": {},
            "布吉": {},
            "坂田": {},
        },
    },
    "湖南":{
        "长沙": {
            "大学城区":{},
        },
        "衡阳":{
            "衡阳":{
                "火车站":{},
            },
        },
        "郴州":{
            "北湖区": {},
            "苏仙区": {},
            "东湖区": {},
        },

    },
    "北京":{},
}

current_layer = menu
parent_layer = []
while True:
    for key in current_layer:
        print(key)
    choice = input(">>>>:").strip()
    if len(choice) == 0:continue
    if choice in current_layer:
        parent_layer.append(current_layer)
        current_layer = current_layer[choice]
    elif choice == "b":
        current_layer = parent_layer.pop()
    else:
        print("NO")