[Python-Dev] Add a "transformdict" to collections
ethan at stoneleaf.us
Wed Sep 11 23:56:22 CEST 2013
On 09/11/2013 02:39 PM, Tim Delaney wrote:
> On 12 September 2013 02:03, Ethan Furman <ethan at stoneleaf.us <mailto:ethan at stoneleaf.us>> wrote:
> On 09/11/2013 08:49 AM, Victor Stinner wrote:
> 2013/9/11 Ethan Furman <ethan at stoneleaf.us <mailto:ethan at stoneleaf.us>>:
> He isn't keeping the key unchanged (notice no white space in MAPPING), he's
> merely providing a function that will automatically strip the whitespace
> from key lookups.
> transformdict keeps the key unchanged, see the first message:
> >>> d = transformdict(str.lower)
> >>> d['Foo'] = 5
> >>> d['foo']
> >>> d['FOO']
> >>> list(d)
> That seems backwards to me. I would think that retrieving the keys from the dict would return the transformed keys (I'd
> call them canonical keys). That way there's no question about which key is stored - it's *always* the transformed key.
At this point there is still no question: it's the first version of the key seen. For a stupid example:
--> d = transformdict(str.lower)
--> d['ThePyramid'] = 'Game Show'
--> d['AtOnce'] = now()
--> for k, v in d.items():
... print(k, v)
Imagine writing a function to get that capitalization right.
> In fact, I think this might get more traction if it were referred to as a canonicalising dictionary (bikeshedding, I know).
Whoa, that's way harder to spell! ;) Drop the 'ising', though, and I'm in.
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