[Python-Dev] PEP 455: TransformDict (original) (raw)

Antoine Pitrou solipsis at pitrou.net
Sat Sep 14 19:41:31 CEST 2013

On Sat, 14 Sep 2013 09:43:13 -0700 Ethan Furman <ethan at stoneleaf.us> wrote:

On 09/14/2013 03:27 AM, Antoine Pitrou wrote: > On Fri, 13 Sep 2013 21:59:11 -0700 > Ethan Furman <ethan at stoneleaf.us> wrote: >> >>> I mean - given no function to retrieve the canonical key, >>> one would have to resort to: >>> >>> mykey = data.transform(givenkey) >>> for key, value in data.items(): >>> if data.transform(key) == mykey: >>> .... >> >> Which is exactly why I, and others, would like to have the transform function easily available. Besides being able to >> use it to get a canonical key, one could use it to get the function itself. Yay, introspection! > > Well, no, you misunderstand :) The transform function takes an > original key (perhaps "canonical") and returns the transformed key, it > can't do the reverse which is what getitem() does. i.e.:

Argh, of course you are right. Still, I think it would be useful to expose the transform function. Any good reason not to?

No good reason. What's the name? transform_func?

Regards

Antoine.

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