On Nov 15, 7:23 pm, Steve Howell <showel...@yahoo.com> wrote: > On Nov 15, 10:25 am, Steve Howell <showel...@yahoo.com> wrote: > > > [see original post...] > > I am most > > interested in the specific mechanism for changing the __getitem__ > > method for a subclass on a dictionary. Thanks in advance! > > Sorry for replying to myself, but I just realized that the last > statement in my original post was a little imprecise. > > I am more precisely looking for a way to change the behavior of foo > ['bar'] (side effects and possibly return value) where "foo" is an > instance of a class that subclasses "dict," and where "foo" is not > created by me. The original post gives more context and example code > that does not work as I expect/desire.
[quote from http://docs.python.org/reference/datamodel.html] For instance, if a class defines a method named __getitem__(), and x is an instance of this class, then x[i] is roughly equivalent to x.__getitem__(i) for old-style classes and type(x).__getitem__(x, i) for new-style classes. [/quote] A quick hack could be: class Al(dict): def __getitem__(self, key): return self.spy(key) def spy(self, key): return 'Al' >>> a = Al() >>> a[3] 'Al' >>> a.spy = lambda key: 'test' >>> a[3] 'test' >>> b = Al() >>> b[3] 'Al' Seems to be what you're after anyway... hth, Jon. -- http://mail.python.org/mailman/listinfo/python-list
