class TestDict:

     name = "wyb"

     age = ""

     def __init__(self):

         self.gender = 'male'

     def keys(self):                         # 获取字典的键

         s = ('name', 'age', 'gender')

         return s

     def __getitem__(self, item):            # 获取键对应的值

         return getattr(self, item)          # getattr获取对象下某个属性的值

 o = TestDict()

 print(dict(o))          # 创建字典 -> 先调用对象下的keys方法再用o["xxx"]获取值([]本质上是调用对象下的__getitem__方法)

 class Base(object):

     def __init__(self):

         self.fields = []

     def __getitem__(self, item):

         return getattr(self, item)

     def keys(self):

         return self.fields

     def hide(self, *keys):                  # 隐藏域

         for key in keys:

             self.fields.remove(key)

         return self

     def append(self, *keys):                # 添加域

         for key in keys:

             self.fields.append(key)

         return self

 class Sx(Base):

     name = "wyb"

     age = 21

     def __init__(self):

         super(Base, self).__init__()

         self.gender = 'male'

         # self.fields定义默认输出字段

         self.fields = ["name", "age"]

 o1 = Sx()

 print(dict(o1))

 o2 = Sx()

 print(dict(o2.hide("age")))

 o3 = Sx()

 print(dict(o3.append("gender")))

 # 输出结果:

 # {'name': 'wyb', 'age': 21}

 # {'name': 'wyb'}

 # {'name': 'wyb', 'age': 21, 'gender': 'male'}