Python之面向对象元类

Python之面向对象元类

　　call方法：

 1 class People:
 2     def __init__(self,name):
 3         self.name=name
 4     #
 5     def __call__(self, *args, **kwargs):
 6         print('call')
 7     #
 8 
 9 p=People('George')
10 print(callable(People))
11 print(callable(p))
12 
13 p()

View Code

　　元类：　　

 1 class People:
 2     def __init__(self,name):
 3         self.name=name
 4 
 5 
 6 p=People('egon')
 7 
 8 
 9 # print(type(p))
10 #
11 # print(type(People))
12 
13 #typer--->类------>对象
14 
15 
16 class Foo:
17     x=1
18     def run(self):
19         pass
20 print(type(Foo))
21 
22 
23 #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
24 def run(self):
25     print('%s is runing' %self.name)
26 
27 class_name='Bar'
28 bases=(object,)
29 class_dic={
30     'x':1,
31     'run':run
32 }
33 
34 Bar=type(class_name,bases,class_dic)
35 print(Bar)
36 print(type(Bar))

View Code

　　自定义元类：

 1 # class Foo(metaclass=type):
 2 #     x=1
 3 #     def run(self):
 4 #         print('running')
 5 #
 6 #
 7 # # type('Foo',(object,),{'x':1,'run':run})
 8 
 9 
10 
11 # class Mymeta(type):
12 #      def __init__(self,class_name,class_bases,class_dic):
13 #          # print(self)
14 #          # print(class_name)
15 #          # print(class_bases)
16 #          # print(class_dic)
17 #          for key in class_dic:
18 #             if not callable(class_dic[key]):continue
19 #             if not class_dic[key].__doc__:
20 #                 raise TypeError('小子，你没写注释，赶紧去写')
21 #
22 #          # type.__init__(self,class_name,class_bases,class_dic)
23 # class Foo(metaclass=Mymeta):
24 #     x=1
25 #     def run(self):
26 #         'run function'
27 #         print('running')
28 
29 # Foo=Mymeta('Foo',(object,),{'x':1,'run':run})
30 
31 # print(Foo.__dict__)
32 
33 
34 
35 class Mymeta(type):
36      def __init__(self,class_name,class_bases,class_dic):
37             pass
38      def __call__(self, *args, **kwargs):
39         # print(self)
40         obj=self.__new__(self)
41         self.__init__(obj,*args,**kwargs) #obj.name='egon'
42         return obj
43 class Foo(metaclass=Mymeta):
44     x=1
45     def __init__(self,name):
46         self.name=name #obj.name='egon'
47     def run(self):
48         'run function'
49         print('running')
50 # print(Foo.__dict__)
51 
52 f=Foo('egon')
53 
54 print(f)
55 
56 print(f.name)

View Code

友情学习链接