Element-wise addition of two list of different lengths?

Question

How to perform element-wise addition of different length lists?
Assuming \"0\" for missing elements.
Note: len(a) will always be less than or equal to len(b)

exa

Answer 1

There's an alternative zip that does not stop at the shortest: itertools.zip_longest(). You can specify a fill value for the shorter lists:

from itertools import zip_longest

result = [sum(n) for n in zip_longest(a, b, fillvalue=0)]