How can I sum a column of a list?

Question

I have a Python array, like so:

[[1,2,3],
 [1,2,3]]

I can add the row by doing sum(array[i]), how can I sum a column, using a

Answer 1

Try this:

a = [[1,2,3],
     [1,2,3]]

print [sum(x) for x in zip(*a)]

zip function description