Variable interpolation question

[anton muhin]

Bengt Richter wrote:
> On Mon, 17 Nov 2003 20:47:51 +0300, anton muhin <antonmuhin.REMOVE.ME.FOR.REAL.MAIL at rambler.ru> wrote:
> 
> 
>>Andrew Fabbro wrote:
>>
>>
>>>This is probably a beginner's question, but I'm stuck...please be kind
>>>to an ex-perler ;)
>>>
>>>How do I do something like this:
>>>
>>>for attr in dir(some_obj):
>>>  if ( some_obj.attr == 0 ):
>>>    print "Missing data: %s field %s" % ( some_obj.name,
>>>some_obj.attr)
>>>
>>>Of course, this gives 
>>>"AttributeError: foo instance has no attribute 'attr'"
>>>
>>>I really don't want to use exec/eval, as that slows things down
>>>dramatically.
>>>
>>>Help?
>>>
>>>Thanks.
>>>
>>>-Drew
>>
>>You are probably looking for hasattr/getattr functions:
>>
>>for attr in dir(some_obj):
>>    if hasattr(some_obj, attr) and getattr(some_obj, attr) == 0:
>>         print 'blah...'
>>
>>of course, it could be shorter:
>>
>>....
>>    if getattr(some_obj, attr, 0) == 0:
>>        print 'blah'
>>
> 
> Or why use an "== 0" test when just hasattr tests for presence/absence without using up
> a possible value of the attribute for flag purposes?
> 
[skipped]
> Regards,
> Bengt Richter

Of course you're right, I just forgot it and thought that OP wants to 
verify attribute's presence as well---mea culpa.

regards,
anton.