对象的属性输出,魔法方法__dict__

In [17]: class Td(): 
    ...:     def __init__(self): 
    ...:         self.a = 1 
    ...:         self.b = '234' 
    ...:                                                                                          

In [18]:                                                                                          

In [18]: td = Td()                                                                                

In [19]: td.__dict__                                                                              
Out[19]: {'a': 1, 'b': '234'}

 其实我们在给对象复制，修改，程序就在调用__ditct__