[EMAIL PROTECTED] wrote: > The use of frozenset can okay when sub-sequences are longer, but for > this problem it's slow, and anyway there are situations of repeated > data like this that have to be considered:
Not just for frozenset; this has to be considered whatever the representation. > > frozenset( ('a', 'a') ) > ==> > frozenset(['a']) > > For Py2.4 the faster and better solution seems Peter Otten one. > James Stroud solution is O(n^2) and it can become slow for long > lists... "Better"? In what sense? My point is that the OP's real problem requires (a) a workable canonical representation of a pair -- lack of this is most probably the root cause of the problem that he is trying to solve!! -- and (b) a result that identifies the duplicate pairs unambiguously so that he can do something with them. "Faster"? The solutions proposed by Peter and James do more-or-less answer the OP's ill-formed question, but speed should be the last consideration, after the real problem is defined carefully. -- http://mail.python.org/mailman/listinfo/python-list