2.实现多级菜单

需求:

1.可依次选择进入各子菜单
2.在各个子菜单可以返回上一级菜单，可以退出.
3. 所需新知识点：列表，字典
流程图：

# -*- coding:utf-8 -*-
# Author: JACK ZHAO

# 作业3：多级菜单
# 三级菜单
# 可依次选择进入各子菜单
# 所需新知识点：列表，字典

mydict = {
            '广东': {
                    '广州':{
                        '越秀区':["越秀公园","中山纪念堂","镇海楼"],
                        '白云区':["白云山","白云湖","南湖游乐园"],
                        '天河区':["花城广场","海心沙","天河体育中心"]},
                    '深圳':{
                        '福田区':["莲花山","少年宫","市民之家"],
                        '南山区':["世界之窗","锦绣中华","海上世界"],
                        '盐田区':["大梅沙","梧桐山","东部华侨城"]
                        }
                     },
            '湖南': {
                    '长沙':{
                         '芙蓉区':["芙蓉广场","晓园公园","马王堆汉墓"],
                         '岳麓区':["岳麓山","橘子洲","大学城"],
                         '开福区':["古开福寺","世界之窗","海底世界"]},
                    '岳阳':{
                         '岳阳楼区':["岳阳楼","岳阳楼公园","三醉亭"],
                         '君山区':["岳阳楼","君山岛","洞庭湖"],
                         '汨罗市':["汨罗江","玉池山","神鼎山"]
                        }
                     },
            '浙江': {
                    '杭州':{
                       '上城区':["清河坊","鼓楼","城隍阁景区"],
                       '下城区':["武林广场","司徒雷登故居","凤凰寺"],
                       '西湖区':["杭州西湖景区","雷峰塔","宋城"]},
                    '宁波':{
                       '海曙区':["天一藏书阁","海曙楼","天封塔"],
                       '江北区':["慈城古县城","保国寺","老外滩"],
                       '北仑区':["太白山","九峰山","洋沙山"]
                 }
            },
        }

print("欢迎使用城市景点查询小工具".center(50,"#"))
while True:
    for index,i in enumerate(mydict): #遍历字典一级菜单
        print(index,i)
    choice1 = input("请输入要查询省份的名称【q|退出】:")
    if  choice1 in mydict:
        while True:
            for index, i in enumerate(mydict[choice1]): #二级菜单
                print(index, i)
            choice2 = input("请输入要查询城市的名称【b|返回，q|退出】:")
            if choice2 in mydict[choice1]:
                while True:
                    for index,i in enumerate(mydict[choice1][choice2]): #三级菜单
                        print(index,i)
                    choice3 = input("请输入要查询市区的名称【b|返回，q|退出】：")
                    if choice3 in mydict[choice1][choice2]:
                        while True:
                            for index, i in enumerate(mydict[choice1][choice2][choice3]): #遍历列表
                                print(index, i)
                            choice4 = input("已经是最后一级菜单，【b|返回，q|退出】：")
                            if choice4 == "q":
                                print("你已退出，欢迎再次光临！")
                                exit()
                            elif choice4 == "b":
                                break
                    elif choice3 == "q":
                        print("你已退出，欢迎再次光临！")
                        exit()
                    elif choice3 == "b":
                        break
                    else:
                        print("你输入的市区\033[31m%s\033[0m不在列表内,请重新输入." % (choice3))
            elif choice2 == "q":
                print("你已退出，欢迎再次光临！")
                exit()
            elif choice2 == "b":
                break
            else:
                print("你输入的城市\033[31m%s\033[0m不在列表内,请重新输入." % (choice2))
    elif choice1 == "q":
        print("你已退出，欢迎再次光临！")
        exit()
    else:
        print("你输入的省份\033[31m%s\033[0m不在列表内,请重新输入." % (choice1))