convert an adjacency list to edge list format

adjacency-list-to-edges.py

import sys
"""
usage:
    python adjacency-list-to-edges.py [adjacency-list-file] [edge-list-file]

example:

    this program will help convert this:

        [adjacency-list-file]
        1 2 3 4 5
        2 1 3 4
        3 1 2 4 6 7

    into this:

        [edge-list-file]
        1 2 1
        1 3 1
        1 4 1
        1 5 1
        2 1 1
        2 3 1
        2 4 1
        3 1 1
        3 2 1
        3 4 1
        3 6 1
        3 7 1
"""

adjacency_list_filename = sys.argv[1]
edge_list_filename = sys.argv[2]

edge_list = []
with open(adjacency_list_filename, 'r') as f:
    for line in f:
        line = line.rstrip('\n').split(' ')
        source = line[0]
        for target in line[1:]:
            edge_list.append("%s %s 1" % (source, target))

with open(edge_list_filename, 'w') as f:
    f.write('%s\n' % ('\n'.join(edge_list)))