__getattr__ and __getattribute__

[km]

Oh thats lucid!
thanks for the explanation.

regards
KM
-------------------------------------------------------------
On 5/9/07, Gabriel Genellina <gagsl-py2 at yahoo.com.ar> wrote:
>
> En Tue, 08 May 2007 08:22:03 -0300, km <srikrishnamohan at gmail.com>
> escribió:
>
> > i find it difficult to understand the difference between the magic
> > methods
> > __getattr__ and __getattribute__
> > and so donot know when to use former or later.
> > can someone  brief me on it ?
>
> This is better understood with a bit of history.
> On earlier Python versions (before 2.2) the only object model available
> was what we now call "classic classes".
> Classic instances hold their attributes in a dictionary, called __dict__.
> Attribute lookup starts at this instance dictionary; if not found,
> continues in the class, and its parent class, all along the inheritance
> tree. If still not found, __getattr__ (if it exists) is called, and should
> return the attribute value or raise AttributeError. That is, __getattr__
> is called *last*, and *only* when the attribute was not previously found
> in the usual places.
>
> Since Python 2.2, there are "new style classes" available; they inherit
> directly or indirectly from object. A new style instance may not even have
> a __dict__. An existing __getattribute__ method is tried *first*; it
> should return the attribute value or raise AttributeError. If no custom
> __getattribute__ exists, the default object.__getattribute__ is used. As a
> last resort, if __getattr__ is defined, it is called.
>
> OTOH, there is a single version of __setattr__, which is always invoked
> when setting an attribute.
>
> --
> Gabriel Genellina
>
> --
> http://mail.python.org/mailman/listinfo/python-list
>
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