How to find the cumulative sum of numbers in a list?

Question

time_interval = [4, 6, 12]

I want to sum up the numbers like [4, 4+6, 4+6+12] in order to get the list t = [4, 10, 22].

Answer 1

lst = [4,6,12]

[sum(lst[:i+1]) for i in xrange(len(lst))]

If you are looking for a more efficient solution (bigger lists?) a generator could be a good call (or just use numpy if you really care about perf).

def gen(lst):
    acu = 0
    for num in lst:
        yield num + acu
        acu += num

print list(gen([4, 6, 12]))