Python之三层菜单

三层菜单，根据用户所选数字，进入子菜单。一级一级呈现。

 menu = {
     'Beijing': {
         "ChaoYang": {
             "CBD": ['CICC', 'CCTV'],
             "JinRongJie": ["CT"],
             "Wangjing": ["Momo", "ChuiZI"]
         },
         "HaiDian": ['Baidu', 'Youku']
     },
     'Shanghai': {
         "PuDong": ["Ctrip", "One Shop"],
         "PuXi": ["China Bank", "America Bank"]
     }
 }
 exit_flag = False
 while not exit_flag:
     for index, key in enumerate(menu.keys()):
         print(index, key)
     choice_1 = input("Please choose menu to enter:").strip()
     if choice_1.isdigit():
         choice_1 = int(choice_1)

         key_1 = list(menu.keys())[choice_1]
         while not exit_flag:
             for index, key in enumerate(menu[key_1]):
                 print('-->', index, key)
             choice_2 = input("Please choose menu to enter:").strip()
             if choice_2.isdigit():
                 choice_2 = int(choice_2)

                 key_2 = list(menu[key_1].keys())[choice_2]
                 while not exit_flag:
                     for index, key in enumerate(menu[key_1][key_2]):
                         print('-->-->', index, key)
                     choice_3 = input("Please choose menu to enter:").strip()
                     if choice_3.isdigit():
                         print("This is the last level...")
                     elif choice_3 == 'quit':
                         exit_flag = True
                     elif choice_3 == 'back':
                         break
 else:
     print("====Going to quit==== ")

注：此版本为Python3.0版本