combinatorics via __future__ generators

[John Yeung]

On Dec 1, 5:55 pm, Phlip <phlip2... at gmail.com> wrote:
> Awesome thanks - but:
>
> > from itertools import imap,product
>
> Do we have a version for Python2.5? I have to support an older server
> here; can't install a newer python on it...

If you can get by with the performance of pure Python, a solution is
right in the documentation for 2.6:

###
def product(*args, **kwds):
    # product('ABCD', 'xy') --> Ax Ay Bx By Cx Cy Dx Dy
    # product(range(2), repeat=3) --> 000 001 010 011 100 101 110 111
    pools = map(tuple, args) * kwds.get('repeat', 1)
    result = [[]]
    for pool in pools:
        result = [x+[y] for x in result for y in pool]
    for prod in result:
        yield tuple(prod)
###

The docs for itertools are full of these definitions (for 2.6
functions) that can be used as recipes (if you don't have 2.6).

John