#!/usr/bin/env python3
# -*- coding: utf-8 -*-

# Copyright (c) 2012 Jérémie DECOCK (http://www.jdhp.org)

# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:

# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

import itertools

def main():
    """Main function"""

    # All possible permutations
    #  combinations(iterable, r) --> combinations object
    #
    # Return successive r-length combinations of elements in the iterable.
    #  combinations(range(4), 3) --> (0,1,2), (0,1,3), (0,2,3), (1,2,3)

    for combination in itertools.combinations(range(4), 3):
        print(combination)

if __name__ == '__main__':
    main()

Add a snippet (Python itertools).