Get all numbers that add up to a number

Question

I\'m trying to find a way to display all the possible sets of X integers that add up to a given integer. for example to get all 2 integer sets that make 5 I would have:

Answer 1

There's a snippet here:

from itertools import combinations, chain

def sum_to_n(n):
    'Generate the series of +ve integer lists which sum to a +ve integer, n.'
    from operator import sub
    b, mid, e = [0], list(range(1, n)), [n]
    splits = (d for i in range(n) for d in combinations(mid, i)) 
    return (list(map(sub, chain(s, e), chain(b, s))) for s in splits)

Use it like this:

for p in sum_to_n(4):    
    print p

Outputs:

[4]
[1, 3]
[2, 2]
[3, 1]
[1, 1, 2]
[1, 2, 1]
[2, 1, 1]
[1, 1, 1, 1]