获取 class 属性的属性名称

Question

这里有两个离散对象：

class Field(object):
    pass

class MyClass(object):
    firstname = Field()
    lastname = Field()
    email = Field()

对于任何 Field 对象，是否有一种固有的方式让该对象知道 MyClass 分配给它的属性名称？

我知道我可以将参数传递给 Field 对象，例如 email = Field(name='email')，但在我的实际情况下这会很混乱和乏味，所以我只是想知道是否有非手动的做同样事情的方法。

谢谢！

Answer 1

是的，你可以让Fieldclass一个descriptor, and then use __set_name__方法来绑定名字。 MyClass.

不需要特殊处理

object.__set_name__(self, owner, name) Called at the time the owning class owner is created. The descriptor has been assigned to name.

这个方法是available in Python 3.6+。

>>> class Field:
...     def __set_name__(self, owner, name):
...         print('__set_name__ was called!')
...         print(f'self: {self!r}')  # this is the Field instance (descriptor)
...         print(f'owner: {owner!r}')  # this is the owning class (e.g. MyClass) 
...         print(f'name: {name!r}')  # the name the descriptor was bound to
... 
>>> class MyClass:
...     potato = Field()
... 
__set_name__ was called!
self: <__main__.Field object at 0xcafef00d>
owner: <class '__main__.MyClass'>
name: 'potato'

获取 class 属性的属性名称

Get attribute name of class attribute

python

python-3.5

python-descriptors