On Tue, Mar 23, 2010 at 5:48 PM, Adam Olsen <rha...@gmail.com> wrote: > a = Decimal('nan') > a != a > > They don't follow the behaviour required for being hashable.
What's this required behaviour? The only rule I'm aware of is that if a == b then hash(a) == hash(b). That's not violated here. Note that containment tests check identity before equality, so there's no problem with putting (float) nans in sets or dicts: >>> x = float('nan') >>> s = {x} >>> x in s True Mark _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com