第一章--三级菜单作业

#_*_coding:utf-8_*_
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‘:{},

        },
        ‘上海‘:{
            ‘闵行‘:{},
            ‘闸北‘:{
                ‘火车站‘:{
                    ‘携程‘:{},

                    },
                }
            },
            ‘浦东‘:{},
            },


while True:
    for k in menu:
        print(k)
    choice = input(">:").strip
    if not choice:continue
    if choice in menu:
      while True:
        for k in menu[choice]:
            print(k)
        choice2=input(">>:").strip()
        if not choice2: continue
        if choice2 in menu[choice]:
            while True:

                for k in menu[choice][choice2]:
                    print(k)
                    choice3 = input(">>>:").strip()
                    if not choice3:continue
                    if choice3 in menu[choice][choice2]:
                        print("go to ,",menu[choice] [choice2] [choice3])
                    else:
                         print("节点不存在")


            else:
                    print("节点不存在")