getting dynamic attribute in python
getattr, python
Solution
How about:
for name in 'a', 'b', 'c':
try:
thing = getattr(obj, name)
except AttributeError:
pass
else:
break
Problem
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) 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' ``` or ``` >>> 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' ``` or ``` >>> 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' ``` 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' ``` Now, I would like to know whether there is a better way to this? As I'm 100% convinced what I've done :) Thanks in advance