Number Pairs (CodeEval) in python 3.x

main.py

# coding=utf-8
import sys
from itertools import combinations


def number_pairs(nums, x):
    return filter(lambda t: sum(t) == x, combinations(nums, 2))


def display_number_pairs(pairs):
    if pairs:
        print(';'.join(['%s,%s' % p for p in pairs]))
    else:
        print('NULL')


def main():
    with open(sys.argv[1], 'r') as f:
        for line in f:
            nums, x = line.rstrip().split(';')
            pairs = number_pairs(map(lambda x: int(x), nums.split(',')), int(x))
            display_number_pairs(pairs)


if __name__ == '__main__':
    main()