三级菜单

题目：

 三级菜单
 打印省、市、县三级菜单 
 可返回上一级                   
 可随时退出程序   

代码：

area = {
    "山东": {
        "青海": {"四方", "🏝️黄岛", "李沧"},
        "济南": {"高新", "🏝️长青", "章丘"},
    },
    "广东": {
            "深圳": {"罗湖", "🏝️南山", "宝安"},
            "广州": {"天河", "🏝️珠海", "白云"},
        },
    "浙江": {
                "杭州": {"西湖", "🏝️下城", "上城"},
                "温州": {"鹿城", "🏝️龙湾", "乐清"},
            }
}
province_list = list(area.keys())
# print(province_list)
while True:
    for i in province_list:
        print(province_list.index(i)+1,i)
    pro_id = input("请输入想进入的省份编号，或者按q退出")
    if pro_id.isdigit():
        pro_id = int(pro_id)
        if pro_id>0 and pro_id<len(province_list):
            pro_name = province_list[pro_id-1]
            # print(pro_name)
            city_list = list(area[pro_name].keys())
            # print(city_list)
            while True:
                for i in city_list:
                    print(city_list.index(i)+1,i)
                city_id = input("请输入想进入的城市编号,或者按q退出，或者按b退回上一级菜单")
                if city_id.isdigit():
                    city_id = int(city_id)
                    if city_id>0 and city_id<len(city_list):
                        city_name = city_list[city_id-1]
                        # print(city_list)
                        town_list = list(area[pro_name][city_name])
                        # print(town_list)
                        while True:
                            for t in town_list:
                                print(town_list.index(t)+1,t)

                            town_id = input("按q退出，或者按b退回上一级菜单")
                            if town_id=="q":
                                exit()
                            elif town_id=="b":
                                break
                elif city_id=="b":
                    break
                elif city_id=="q":
                    exit()
    elif pro_id=="q":
        exit()