在python中获取动态属性 [英] getting dynamic attribute in python

问题描述

我有一个带有 pseudo 或 special 属性的对象，该属性可以用三种不同的方式命名(注意:我不控制生成该对象的代码)

I have and object with an pseudo or special attribute that can be named in three different ways (Note: I don't control the code which generates the object)

属性中的值(取决于设置的是哪个)是完全相同的，我需要获取该值以进行进一步处理，因此根据数据源，我可以得到类似以下内容的东西:

The value in the attributes (depending which one is set) is exactly the same, and I need to get that for further processing, so depending of the source of data, I can have something like:

>>> obj.a
'value'
>>> obj.b
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: Obj instance has no attribute 'b'
>>> obj.c
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: Obj instance has no attribute 'c'

或

>>> obj.a
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: Obj instance has no attribute 'a'
>>> obj.b
'value'
>>> obj.c
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: Obj instance has no attribute 'c'

或

>>> obj.a
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: Obj instance has no attribute 'a'
>>> obj.b
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: Obj instance has no attribute 'b'
 >>> obj.c
'value'

我对获取'value'感兴趣，但是不幸的是，该对象中不存在__dict__属性.因此，我为获得该价值而结束的工作只是做一堆getattr调用.假设可能性只有三种，则代码如下所示:

I'm interested in getting 'value' and unfortunately __dict__ property does not exist in that object. So what I ended doing for getting that value was just do a bunch of getattr calls. Assuming that possibilities are only three, the code looked like this:

>>> g = lambda o, l: getattr(o, l[0], getattr(o, l[1], getattr(o, l[2], None)))
>>> g(obj, ('a', 'b', 'c'))
'value'

现在，我想知道是否有更好的方法?当我100％相信自己所做的事情时:)

Now, I would like to know whether there is a better way to this? As I'm 100% convinced what I've done :)

预先感谢

推荐答案

怎么样:

for name in 'a', 'b', 'c':
    try:
        thing = getattr(obj, name)
    except AttributeError:
        pass
    else:
        break

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