On Fri, Nov 2, 2018 at 12:07 PM Alex Shafer <ashafe...@gmail.com> wrote: > Other APIs I've considered for this are a new keyword argument to the > existing `setdefault()`, or perhaps more radically for Python, a new keyword > argument to the `dict()` constructor that would get called as an implicit > default for `setdefault()` and perhaps used in other scenarios (essentially > defining a type for dict values). >
The time machine has been put to good use here. Are you aware of __missing__ and collections.defaultdict? You just create a defaultdict with a callable (very common to use a class like "list"), and any time you try to use something that's missing, it'll call that to generate a value. from collections import defaultdict d = defaultdict(list) for category, item in some_stuff: d[category].append(item) Easy way to group things into their categories. ChrisA _______________________________________________ Python-ideas mailing list Python-ideas@python.org https://mail.python.org/mailman/listinfo/python-ideas Code of Conduct: http://python.org/psf/codeofconduct/