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

Eric Fahlgren ericfahlgren at gmail.com
Fri Dec 22 10:44:25 EST 2017


On Thu, Dec 21, 2017 at 7:51 PM, Stephen J. Turnbull < turnbull.stephen.fw at u.tsukuba.ac.jp> wrote:

I understand the motivation to guarantee order, but it's a programmer convenience that has nothing to do with the idea of mapping, and the particular (insertion) order is very special and usually neither relevant nor reproducible. I have no problem whatsoever with just documenting any failure to preserve order while reproducing dicts, except that a process that inserts keys in the same order had better result in the same insertion order.

​json, pickle == png, i.e., guaranteed lossless. repr, pprint == jpg, lossy for very specific motivating reasons.​

In particular, I use pprint output in regression baselines, and if the long documented sort-by-key behavior changed, I would not be happy. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://mail.python.org/pipermail/python-dev/attachments/20171222/896f8126/attachment.html>



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