On Tue, 10 Sep 2013 14:44:01 +0200 "Martin v. Löwis" firstname.lastname@example.org wrote:
Am 10.09.13 14:35, schrieb Antoine Pitrou:
['FOO'] or ['foo']? Both answers are justifiable. Both are possibly even useful depending on context...
I think it would be best to leave it as an implementation detail, because whichever is easiest to implement depends on the exact implementation choices (e.g. C vs. Python).
I think this is the point where the datatype is *not* clearly straight-forward, and thus deserves a PEP.
Not saying you're necessary wrong, but a few data points: - defaultdict was added without a PEP: http://bugs.python.org/issue1433928 - Counter was added without a PEP: http://bugs.python.org/issue1696199 - ChainMap was added without a PEP: http://bugs.python.org/issue11089 http://bugs.python.org/issue11297 - namedtuple was added without a PEP: https://mail.python.org/pipermail/python-dev/2007-February/071196.html (no tracker reference for its addition)
OrderedDict, however, came with a PEP: http://www.python.org/dev/peps/pep-0372/
I think it would be a flaw to have this detail implementation-defined. This would be like saying that it is implementation-defined which of A,B,C is returned from "A and B and C" if all are true.
Ok, it seems everyone (except me :-)) agrees that it should return the first key value, so that's how it will be.