On 07/02/2010 11:26 AM, Chris Rebert wrote: > On Fri, Jul 2, 2010 at 2:20 AM, Thomas Jollans <tho...@jollans.com> wrote: >> On 07/02/2010 06:11 AM, Steven D'Aprano wrote: >>> I would like to better understand some of the design choices made in >>> collections.defaultdict. > <snip> >>> Second, why is the factory function not called with key? There are three >>> obvious kinds of "default values" a dict might want, in order of more-to- >>> less general: >>> >>> (1) The default value depends on the key in some way: return factory(key) >> >> I agree, this is a strange choice. However, nothing's stopping you from >> being a bit verbose about what you want and just doing it: >> >> class mydict(defaultdict): >> def __missing__(self, key): >> # ... >> >> the __missing__ method is really the more useful bit the defaultdict >> class adds, by the looks of it. > > Nitpick: You only need to subclass dict, not defaultdict, to use > __missing__(). See the part of the docs Raymond Hettinger quoted. >
Sorry Raymond, I didn't see you. This is where I cancel my "filter out google groups users" experiment. -- http://mail.python.org/mailman/listinfo/python-list
