item系列

# # # item 系列与[]去访问值有联系
# # obj = {"K" : "V"}
# # print(obj)  # 字典的对象
# # print(obj["K"])
# 
# # class B:
# #     def __getitem__(self, item):
# #         print("执行我了")
# #         return "BBBB"
# #
# #     def __setitem__(self, key, value):
# #         print(key,value)
# #
# # b = B()
# # # print(b["a"])
# # # print(b["k"])
# # b["k"] = "value"
# # print(b["k"])
# 
# 
# # 在内置的模块中一些特殊的方法要求必须实现 __getitem__，__setitem__  才能实现
# # class B:
# #     def __getitem__(self, item):
# #         return getattr(self,item)
# #
# #     def __setitem__(self, key, value):
# #         setattr(self,key,value)
# #     def __delitem__(self, key):
# #         # print(key)
# #         delattr(self,key)
# #
# # b = B()
# # b["k1"] = "v1"   #__setitem__
# # print(b["k1"])    # __getitem__
# # del b["k1"]     # __delitem__
# # print(b["k1"])
# 
# class C:
#     def __init__(self,lst):
#         self.lst = lst
# 
#     def __setitem__(self, key, value):
#         self.lst[key] = value
#     def __getitem__(self, item):
#         return self.lst[item]
#     def __delitem__(self, key):
#         self.lst.pop(key)
# 
# c = C([1,2,3,4,5,6])
# print(c[0])
# c[0] = "999"
# print(c[0])
# del c[0]
# print(c.lst)


# 类
# 每一个对象都是扑克牌
# 查看每个对象来查看整幅牌，
# 从这一副牌中随机抽取一张牌
# 打乱这副牌顺序的功能