Compute the cumulative sum of a list until a zero appears

Question

I have a (long) list in which zeros and ones appear at random:

list_a = [1, 1, 1, 0, 1, 1, 0, 1, 0, 1, 1, 1]

I want to get the list_b

Answer 1

It doesn't have to be as complicated as made in the question asked, a very simple approach could be this.

list_a = [1, 1, 1, 0, 1, 1, 0, 1, 0, 1, 1, 1]
list_b = []
s = 0
for a in list_a:
    s = a+s if a !=0 else 0
    list_b.append(s)

print list_b