Python3学习之路~2.5 简单的三级菜单程序

程序：
三级菜单

需求：

1.打印省、市、县三级菜单
2.可返回上一级
3.可随时退出程序

代码1：

data={
    "山东":{
        "济南":["历下区","高新区","长清区"],
        "日照":["东港区","五莲县","岚山区"],
        "青岛":["崂山区","黄岛区","市中区"]
    },
    "陕西": {
        "西安": ["雁塔区", "高新区", "未央区"],
        "延安": ["宝塔区", "宜川县", "黄陵县"],
        "宝鸡": ["陈仓区", "岐山县", "太白县"]
    }
}

while True:
    for i in data:
        print(i)
    choice = input("请选择进入：")
    if choice in data:
        while True:
            for i2 in data[choice]:
                print('\t',i2)
            choice2 = input("请选择进入：")
            if choice2 in data[choice]:
                while True:
                    for i3 in data[choice][choice2]:
                        print('\t\t',i3)
                    choice3=input("最后一级，请输入q退出或输入b返回上一级：")
                    if choice3 == 'b':
                        break
                    elif choice3 == 'q':
                        exit()
                    else:
                        print("无效输入！")
            elif choice2 == 'b':
                break
            elif choice2 == 'q':
                exit()
            else:
                print("无效输入！")
    elif choice == 'q':
        exit()
    else:
        print("无效输入！")

代码2：

menu = {
    '北京':{
        '海淀':{
            '五道口':{
                'soho':{},
                '网易':{},
                'google':{}
            },
            '中关村':{
                '爱奇艺':{},
                '汽车之家':{},
                'youku':{},
            },
            '上地':{
                '百度':{},
            },
        },
        '昌平':{
            '沙河':{
                '老男孩':{},
                '北航':{},
            },
            '天通苑':{},
            '回龙观':{},
        },
        '朝阳':{},
        '东城':{},
    },
    '上海':{
        '闵行':{
            "人民广场":{
                '炸鸡店':{}
            }
        },
        '闸北':{
            '火车战':{
                '携程':{}
            }
        },
        '浦东':{},
    },
    '山东':{},
}

exit_flag = False
current_layer = menu

layers = [menu]

while not  exit_flag:
    for k in current_layer:
        print(k)
    choice = input(">>:").strip()
    if choice == "b":
        current_layer = layers[-1]
        #print("change to laster", current_layer)
        layers.pop()
    elif choice not  in current_layer:continue
    else:
        layers.append(current_layer)
        current_layer = current_layer[choice]