PEP: add __sum__ method

Steven D'Aprano steve+comp.lang.python at
Sun Jan 22 07:08:23 EST 2012

On Sun, 22 Jan 2012 03:15:48 -0800, dmitrey wrote:

> hi all,
> could you consider adding __sum__ method, e.g. Python sum(a) checks does
> a have attribute __sum__ and if it has, then a.__sum__() is invoked
> instead of Python sum(a).
> (for my soft FuncDesigner it would be very essential, I guess for many
> other soft as well, e.g. for PuLP, who has to use lpSum, because
> ordinary Python sum slows it very much, as well as my funcs, and for
> large-scale problems max recursion depth is exeeded). Regards, D.

A cautious +0.5 on that. I think I would need to see more detailed 
justification before making it +1.


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