computing a weighted sum

[Raymond Hettinger]

[Christos TZOTZIOY Georgiou]
> Anyway, a functional equivalent:
>
> .>> from itertools import starmap, izip
> .>> import operator
> .>> x= [1,2,3,4]
> .>> w=[3.0, 6.0, 9.0, 12.0]
> .>> sum(starmap(operator.mul, izip(x,w)))
> 90.0

Gack!  starmap() is only for situations where the data is already in tuple form.
If it inputs are already distinct, imap() is the preferred form.

FWIW, the answer was already in the docs (itertools recipes):

    def dotproduct(vec1, vec2):
        return sum(imap(operator.mul, vec1, vec2))


Raymond Hettinger