A slightly better version, only walks the set of cumulative list of sets once per pairing.
-- Paul . import sets . . input = [[1, 2], [3, 4], [2, 3], [4, 5]] . input = [[1, 2], [3, 4], [4, 5]] . input = [[1, 2],[2,1], [3, 4], [4, 5],[2,2],[2,3],[6,6]] . .def merge(pairings): . ret = [] . for a,b in pairings: . aset = None . bset = None . for s in ret: . if not aset and a in s: . aset = s . if not bset and b in s: . bset = s . if aset and bset: . break . else: . if aset: . aset.add(b) . elif bset: . bset.add(a) . else: . ret.append(sets.Set([a,b])) . continue . if aset is not bset: . ret.remove(aset) . ret.remove(bset) . ret.append(aset.union(bset)) . . return [list(s) for s in ret] . .print merge(input) -- http://mail.python.org/mailman/listinfo/python-list
