Variable interpolation question

[anton muhin]

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'

regards,
anton.