data structure design question

[Skip Montanaro]

    Felix> I'm thinking of trying to do some chemistry stuff in Python, and
    Felix> one of the things I was thinking of was to define a Chemical (or
    Felix> Molecule) object. 

Before you go too far, you might want to investigate Konrad Hinsen's
Molecular Modelling Toolkit:

    http://starship.python.net/crew/hinsen/MMTK/

I think you'll find Konrad has advanced well beyond the "thinking" stage of
the project... ;-)

Skip Montanaro | http://www.mojam.com/
skip at mojam.com | http://www.musi-cal.com/
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