# Author :Gao ling data = {
      '北京':{
          "昌平":{
              "沙河":["oldboy","test"],             "天通苑":["链家地产","我爱我家"]         },         "朝阳":{
              "望京":["奔驰","陌陌"],             "国贸":["CICC","HP"],             "东直门":["Advent","飞信"]         },         "海淀":{},     },     '山东':{
          "德州":{},         "青岛":{},         "济南":{}     },     '广东':{
          "东莞":{},         "常熟":{},         "佛上":{}     }, } exit_flag = False while not exit_flag:     for i in data:         print(i)     choice = input("选择进入1>>:")     if choice in data:         while not exit_flag:             for i2 in data[choice]:                 print("\t",i2)             choice2 = input("选择进入2>>:")             if choice2 in data[choice]:                     while not exit_flag:                         for i3 in data[choice][choice2]:                             print("\t\t",i3)                         choice3 = input("选择进入3>>:")                         if choice3 in data[choice][choice2]:                                 for i4 in data[choice][choice2][choice3]:                                     print("\t\t",i4)                                 choice4 = input("最后一层，按b返回>>:")                                 if choice4 =="b":                                     pass                                 elif choice4 =="q":                                     exit_flag=True                         if choice3== "b":                             break                         elif choice3 == "q":                             exit_flag = True             if choice2 == "b":                 break             elif choice2 == "q":                 exit_flag = True