On Fri, 19 Jul 2013 16:47:36 -0700 Ethan Furman <et...@stoneleaf.us> wrote: > While working on issue #18508 I stumbled across this: > > Traceback (most recent call last): > ... > File "/usr/local/lib/python3.4/enum.py", line 417, in __new__ > if value in cls._value2member_map: > TypeError: unhashable type: 'list' > > I'll wrap it in a try-except block, but I must admit I was surprised the > answer wasn't False. After all, if the input > is unhashable then obviously it's not in the dict; furthermore, if I were to > compare the number 5 with a set() I would > get False, not a TypeMismatch error, and dict keys are basically done by > equality, the hash is just (?) a speed-up.
Testing containment of an unhashable key in a dict is a programming error, so I'd prefer that we keep the TypeError here. Same reasoning as for: >>> 5 in "abc" Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: 'in <string>' requires string as left operand, not int Sure, 5 technically isn't in "abc" and therefore the "in" operator could return False, but it's better to highlight the programming error. Regards Antoine. _______________________________________________ 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
