Python之面向对象元类

Python之面向对象元类

　　call方法：

 class People:
     def __init__(self,name):
         self.name=name
     #
     def __call__(self, *args, **kwargs):
         print('call')
     #

 p=People('George')
 print(callable(People))
 print(callable(p))

 p()

　　元类：　　

 class People:
     def __init__(self,name):
         self.name=name

 p=People('egon')

 # print(type(p))
 #
 # print(type(People))

 #typer--->类------>对象

 class Foo:
     x=1
     def run(self):
         pass
 print(type(Foo))

 #type成为元类，是所有类的类，利用type模拟class关键字的创建类的过程
 def run(self):
     print('%s is runing' %self.name)

 class_name='Bar'
 bases=(object,)
 class_dic={
     'x':1,
     'run':run
 }

 Bar=type(class_name,bases,class_dic)
 print(Bar)
 print(type(Bar))

　　自定义元类：

 # class Foo(metaclass=type):
 #     x=1
 #     def run(self):
 #         print('running')
 #
 #
 # # type('Foo',(object,),{'x':1,'run':run})

 # class Mymeta(type):
 #      def __init__(self,class_name,class_bases,class_dic):
 #          # print(self)
 #          # print(class_name)
 #          # print(class_bases)
 #          # print(class_dic)
 #          for key in class_dic:
 #             if not callable(class_dic[key]):continue
 #             if not class_dic[key].__doc__:
 #                 raise TypeError('小子，你没写注释，赶紧去写')
 #
 #          # type.__init__(self,class_name,class_bases,class_dic)
 # class Foo(metaclass=Mymeta):
 #     x=1
 #     def run(self):
 #         'run function'
 #         print('running')

 # Foo=Mymeta('Foo',(object,),{'x':1,'run':run})

 # print(Foo.__dict__)

 class Mymeta(type):
      def __init__(self,class_name,class_bases,class_dic):
             pass
      def __call__(self, *args, **kwargs):
         # print(self)
         obj=self.__new__(self)
         self.__init__(obj,*args,**kwargs) #obj.name='egon'
         return obj
 class Foo(metaclass=Mymeta):
     x=1
     def __init__(self,name):
         self.name=name #obj.name='egon'
     def run(self):
         'run function'
         print('running')
 # print(Foo.__dict__)

 f=Foo('egon')

 print(f)

 print(f.name)

友情学习链接