Can I run an operation on an object's attribute when reading?

Ben Finney bignose+hates-spam at
Mon Jan 19 13:33:14 CET 2009

Phillip B Oldham <phillip.oldham at> writes:

> Thanks, but I'm looking for a way to do it *without* using a getter
> as I don't have easy access to the class (its being generated for me
> elsewhere). Essentially I'd like to overwrite (if possible) the
> default behavior when returning certain attributes on certain
> objects.

You can override the behaviour of a class by defining a subclass.

    class UntouchableTypeWrapper(UntouchableType):

        def _foo_get(self):
            return str(

        foo = property(_foo_get)

Then you can create instances of the wrapper class where you want the
new behaviour.

 \          “… a Microsoft Certified System Engineer is to information |
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Ben Finney

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