[Python-Dev] getattr vs hashattr

[Brett Cannon]

On Fri, Mar 14, 2014 at 3:01 PM, Chris Withers <chris at simplistix.co.uk>wrote:

> On 03/12/2014 04:49 PM, Chris Angelico wrote:
>>
>>> You can use hasattr() in place of AttributeError
>>>
>>
> Is that true now? It used to be that hasattr swallowed all exceptions
> rather than just AttributeError making is a very dangerous weapon for
> anything (such as an orm or odb) that might do something interesting when
> you try and get an attribute from it.
>

Changed in Python 3.2: http://docs.python.org/3.2/whatsnew/3.2.html


>
> On 12/03/2014 21:37, Tres Seaver wrote:
>
>> I use:
>>
>>   getattr(subject, attrname, default)?
>>
>> *all the time*.
>>
>
> On this one, did anything ever come of making getattr have a default
> default of None?


No. If you want None returned as the default you still need to specify that
to allow for those APIs where the attribute can have a value of None but
you still want it to raise an AttributeError if the attribute isn't there.

-Brett


>
>
> Chris
>
> --
> Simplistix - Content Management, Batch Processing & Python Consulting
>             - http://www.simplistix.co.uk
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