Non biased return a list of n random positive numbers (>=0) so that their sum == total_sum

Question

I\'m either looking for an algorithm or a suggestion to improve my code to generate a list of random numbers that their sum equals some arbitrary number. With my code below

Answer 1

The following is quite simple, and returns uniform results:

def gen_list(numbs, limit_sum):
    limits = sorted([random.uniform(0, limit_sum) for _ in xrange(numbs-1)])
    limits = [0] + limits + [limit_sum]
    return [x1-x0 for (x0, x1) in zip(limits[:-1], limits[1:])]

The idea is simply that if you need, say, 5 numbers between 0 and 20, you can simply put 4 "limits" between 0 and 20, and you get a partition of the (0, 20) interval. The random numbers that you want are simply the lengths of the 5 intervals in the sorted list [0, random1, random2, random3, random4, 20].

PS: oops! looks like it's the same idea as MAK's response, albeit coded without using indexes!