[Python-Dev] Guarantee ordered dict literals in v3.7? (original) (raw)

Chris Barker chris.barker at noaa.gov
Mon Dec 18 23:28:52 EST 2017

On Mon, Dec 18, 2017 at 7:41 PM, Steven D'Aprano <steve at pearwood.info> wrote:

> With arbitrary order, it made sense to sort, so as to always give the same > "pretty" representation. But now that order is "part of" the dict itself, > it seems prettyprint should present the preserved order of the dict.

I disagree. Many uses of dicts are still conceptually unordered, even if the dict now preserves insertion order. For those use-cases, insertion order is of no interest whatsoever, and sorting is still "prettier".

and many uses of dicts have "sorted" order as completely irrelevant, and sorting them arbitrarily is not necessarily pretty (you can't provide a sort key can you? -- so yes, it's arbitrary)

I'm not necessarily saying we should break things, but I won't agree that pprint sorting dicts is the "right" interface for what is actually an order-preserving mapping.

I would think it was only the right choice in the first place in order (get it?) to get a consistent representation, not because sorting was a good thing per se.

-Chris

--

Christopher Barker, Ph.D. Oceanographer

Emergency Response Division NOAA/NOS/OR&R (206) 526-6959 voice 7600 Sand Point Way NE (206) 526-6329 fax Seattle, WA 98115 (206) 526-6317 main reception

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