how to cause a request for a missing class attribute cause its calculation

[Vincent Davis]

Lets say I have
class foo(object):
    def __init__(self, x, y):
        self.x=x
        self.y=y
    def xplusy(self):
        self.xy = x+y

inst = foo(1,2)
inst.xy   # no value, but I what this to cause the calculation of inst.xy

I don't what to have self.xy calculated before it is called.


Thanks

*Vincent Davis
720-301-3003 *
vincent at vincentdavis.net
 my blog <http://vincentdavis.net> |
LinkedIn<http://www.linkedin.com/in/vincentdavis>
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