How to know if an object has an attribute in Python

Question

Is there a way in Python to determine if an object has some attribute? For example:

>>> a = SomeClass()
>>> a.someProperty = value
>>         


        

Answer 1

I think what you are looking for is hasattr. However, I'd recommend something like this if you want to detect python properties-

try:
    getattr(someObject, 'someProperty')         
except AttributeError:
    print "Doesn't exist"
else
    print "Exists"

The disadvantage here is that attribute errors in the properties __get__ code are also caught.

Otherwise, do-

if hasattr(someObject, 'someProp'):
    #Access someProp/ set someProp
    pass

Docs:http://docs.python.org/library/functions.html
Warning:
The reason for my recommendation is that hasattr doesn't detect properties.
Link:http://mail.python.org/pipermail/python-dev/2005-December/058498.html