David Eppstein's code is very nice. Here's the python version of the perl code:
�# -*- coding: utf-8 -*- �# Python � �def combo (n): � '''returns all possible (unordered) pairs out of n numbers 1 to n. � � Returns a dictionary. The keys are of the form "n,m", � and their values are tuples. e.g. combo(4) returns � {'3,4': (3, 4), '1,4': (1, 4), '1,2': (1, 2), � '1,3': (1, 3), '2,4': (2, 4), '2,3': (2, 3)}''' � result={} � for j in range(1,n): � for i in range(1,n+1): � m = ((i+j)-1) % n + 1 � if (i < m): � result["%d,%d"%(i,m)]=(i,m) � return result � �print combo(4) So sweet. Xah [EMAIL PROTECTED] http://xahlee.org/PageTwo_dir/more.html -- http://mail.python.org/mailman/listinfo/python-list