动态地向类添加描述符

Question

I've a class with lots of attributes and to cut down on the complexity I'm trying to re-write it by dynamically creating them. I've tried the following:

class D_test: 
    def __get__(self, obj = None, obj_type= None): 
        print (f'{self} yeah!!') 
    def __set__(self, obj, value): 
        print (f'{self} {obj} {value}') 

class Blagh:
    pass

setattr(Blagh, 'test', D_test)

x = Blagh()

x.test

In [18]: x.test                                                                 
Out[18]: __main__.D_test

My understanding is that the above should call the __get__ of the descriptor. Where am I going wrong?

Answer 1

您需要创建描述符的实例，否则您只需将描述符类附加到Blagh ：

setattr(Blagh, 'test', D_test())