What is the pythonic way to calculate dot product?

Question

I have two lists, one is named as A, another is named as B. Each element in A is a triple, and each element in B is just an number. I would like to calculate the result defi

Answer 1

My favorite Pythonic dot product is:

sum([i*j for (i, j) in zip(list1, list2)])

So for your case we could do:

sum([i*j for (i, j) in zip([K[0] for K in A], B)])

Answer 2

Probably the most Pythonic way for this kind of thing is to use numpy. ;-)

Answer 3

>>> X = [2,3,5,7,11]
>>> Y = [13,17,19,23,29]
>>> dot = lambda X, Y: sum(map(lambda x, y: x * y, X, Y))
>>> dot(X, Y)
652

And that's it.

Answer 4

Using more_itertools, a third-party library that implements the dotproduct itertools recipe:

import more_itertools as mit


a = [1, 2, 3]
b = [7, 8, 9]

mit.dotproduct(a, b)
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