Python字典嵌套

 import  copy
 menu = {
     "计算机科学与技术":{
         "程序编程":{
            "传统语言":{
                "C++":"LLWH",
                "C#":"从入门到入土",
                "C#":"haha C#",
            },
             "网站编程":
                 {
                     "PHP":"论坛",
                     "Java":"电商网站",
                     "Python":"全栈开发",

                 },
             "服务器编程":
                 {
                     "视频服务器":"C++",
                     "游戏服务器":"python",
                     "棋牌服务器":"go 语言"
                 },
         },
         "网页设计":{
             "前端":
                 {
                     "优化":"CSS",
                     "格局":"HTML",
                     "数据交换":"JavaScript",
                 },
             "后端":
                 {
                     "服务器":"Linux",
                 }

         }
     }

 }
 menu_copy = copy.deepcopy(menu)

 #print(menu_copy.pop("计算机科学与技术")) # 字典嵌套只能删除第一层
 #print("***"*30)
 for x in menu_copy:
     for x01 in  menu_copy[x]:
         print("-->根节点是{0}\n".format(x01))
         if x01 is not None:
             for x02 in  menu_copy[x][x01]:
                 print("-------->子节点是{0}\n".format(x02))
                 if x02 is not None:
                     for x03 in menu_copy[x][x01][x02]:
                         print("------------>key    {0}, value  {1}\n ".format(x03,menu_copy[x][x01][x02][x03]))

 #print(menu_copy.keys())# 返回 第一个嵌套的子节点