weakref confusion

Jeff Epler jepler at unpythonic.net
Wed Feb 25 22:49:57 CET 2004


On Wed, Feb 25, 2004 at 06:36:59PM +0100, Mathias Mamsch wrote:
> Hi,
> 
> I have some confusion concerning the weakref module.

This is because the class dictionary holds a '<function Test>', but the
expression 'A.Test' returns an '<unbound method A.Test>'.  You can
understand why this is the case by looking at what happens in a
subclass:
    >>> class A:
    ...     def m(): pass
    >>> class B(A): pass
    >>> A.m, B.m
    (<unbound method A.m>, <unbound method B.m>)
    >>> A.__dict__['m']
    <function m at 0x813adfc>

just like bound methods on instances, unbound methods are created "on
demand", and are tied to the class that the attribute reference was
performed on.

Jeff




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