Python adding up number in a list with every 3 number
===

I have a list of numbers go in one row like this:

    0
    1
    0
    2
    0
    4

and it has about thousands of rows

I want to add them up every 3 rows so the results will be like this:

    1
    6

I have already made the list into individual interger with this line:

    k = map(lambda s: s.strip(), k)
    interger = map(int, k)

How would I able to do the adding up?
