python sum the values of lists of list

Question

I have list of lists and i need to sum the inner lists, for example,

a = [[1,2,3], [2,1,4], [4,3,6]]

for my case, the len of a[i] is same,

Answer 1

A simple answer.

a = [[1,2,3], [2,1,4], [4,3,6]]
result = [sum(l) for l in a]

result
[6, 7, 13]

Answer 2

I know that no one like it but just to give an option:

result = [reduce(lambda x, y: x+y, l) for l in a]

Answer 3

result = map(sum, a)

Is the way I would do it. Alternatively:

result = [sum(b) for b in a]

The second variation is the same as yours, except it avoids the unnecessary range statement. In Python, you can iterate over lists directly without having to keep a separate variable as an index.