Python学习第二天-编写三级菜单

编写三级菜单：
1. 运行程序输出第一级菜单
2. 选择一级菜单某项，输出二级菜单，同理输出三级菜单
3. 菜单数据保存在文件中
4. 让用户选择是否要退出
5. 有返回上一级菜单的功能

 # Author: zfh

 data = {
     "陕西":{
         "汉中":["张骞故里","古汉台"],
         "西安":[],
         "商洛":[]
     },
     "山西":{
         "太远":[],
         "运城":[],
         "平凉":[]
     },
     "山东":{
         "青岛":[],
         "济南":[],
         "聊城":[]
     }
 }
 exit_flag = False
 while not exit_flag:
     for i in data:
         print(i)
     choice = input("请输入选择1>>:")
     if choice in data:
         while not exit_flag:
             for i1 in data[choice]:
                 print("\t",i1)
             choice1 = input("请输入选择2>>:")
             if choice1 in data[choice]:
                 while not exit_flag:
                     for i2 in data[choice][choice1]:
                         print("\t\t",i2)
                     choice2 = input("最后一层，按b返回>>:")
                     if choice2 == "b":
                         pass
                     elif choice2 == "q":
                         exit_flag = True
             if choice1 == "b":
                 break
             elif choice1 == "q":
                 exit_flag = True
     if choice == "b":
         break
     elif choice =="q":
         exit_flag = True