Python 三级菜单练习2.0

city_dict={
    '浙江': {'杭州': {'西湖': {}, '上城': {}, '下城': {}}, '宁波': {'江东': {}, '江北': {}, '北仑': {}}, '温州': {'鹿城': {}, '平阳': {}, '龙湾': {}}},
    '江苏': {'苏州': {'常熟': {}, '太仓': {}, '昆山': {}}, '无锡': {'江阴': {}, '宜兴': {}, '惠山': {}}, '常州': {'天宁': {}, '武进': {}, '钟楼': {}}},
    '广东': {'广州': {'天河': {}, '白云': {}, '黄埔': {}}, '深圳': {'罗湖': {}, '福田': {}, '南山': {}}, '东莞': {'莞城': {}, '虎门': {}, '万江': {}}}
}

menu = []

while True:
    for key in city_dict:
        print(key)
    choice = input('>>>:').strip()
    if len(choice) == 0: continue
    if choice in city_dict:
        menu.append(city_dict)
        city_dict = city_dict[choice]
    elif choice == 'q': break
    elif choice == 'b':
        if menu:
            city_dict = menu.pop()
    else: print('查无此项')