Why is Python's OrderedDict ordered?
piglei.com
Why is Python's OrderedDict ordered?
1–10 of 18 posts
Re: Why is Python's OrderedDict ordered?
#2Title of the article is "How…", not "Why…", and "why" is not discussed. (My understanding is that the "why" is "because the implementation acted that way without an official guarantee, and folks depended on the implementation detail, so it became guaranteed.)
Re: Why is Python's OrderedDict ordered?
#3Wrong title, article has "How Does Python’s OrderedDict Maintain Order?"
Re: Why is Python's OrderedDict ordered?
#4Title of the article is "How…", not "Why…", and "why" is not discussed. (My understanding is that the "why" is "because the implementation acted that way without an official guarantee, and folks depended on the implementation detail, so it became guaranteed.)
I don't think this is the "why". What you're depicting is what happened in JavaScript. Dictionary keys in Python always had that (to me) annoying property that they preserved insertion order until they don't. I'd frankly much prefer if they'd always be iterated in random order each time they're traversed.
Re: Why is Python's OrderedDict ordered?
#5Title of the article is "How…", not "Why…", and "why" is not discussed. (My understanding is that the "why" is "because the implementation acted that way without an official guarantee, and folks depended on the implementation detail, so it became guaranteed.)
I don't think this is the "why". What you're depicting is what happened in JavaScript. Dictionary keys in Python always had that (to me) annoying property that they preserved insertion order until they don't. I'd frankly much prefer if they'd always be iterated in random order each time they're traversed.
I'd love to see the results of mandating a random order dict impl at an actual company/org (but hate to be forced to participate). Hopefully you hired developers who really like to write sorting algos.
Re: Why is Python's OrderedDict ordered?
#6Earlier quoted context omitted.
I don't think this is the "why". What you're depicting is what happened in JavaScript. Dictionary keys in Python always had that (to me) annoying property that they preserved insertion order until they don't. I'd frankly much prefer if they'd always be iterated in random order each time they're traversed.
I'd love to see the results of mandating a random order dict impl at an actual company/org (but hate to be forced to participate). Hopefully you hired developers who really like to write sorting algos.
Well, that is how hash tables in go works, so you'd not have to look that far.
Re: Why is Python's OrderedDict ordered?
#7Title of the article is "How…", not "Why…", and "why" is not discussed. (My understanding is that the "why" is "because the implementation acted that way without an official guarantee, and folks depended on the implementation detail, so it became guaranteed.)
I was under that impression as well, but it was added as an implementation in 3.6 (https://bugs.python.org/issue27350), so I don't know that too many people would have become dependent on it before it was official in 3.7: https://docs.python.org/3/whatsnew/3.7.html
I think the "how/why" thing is just the automatic title de-clickbait-ifer going a little haywire?
Re: Why is Python's OrderedDict ordered?
#8Earlier quoted context omitted.
I'd love to see the results of mandating a random order dict impl at an actual company/org (but hate to be forced to participate). Hopefully you hired developers who really like to write sorting algos.
Well, that is how hash tables in go works, so you'd not have to look that far.
Great. Maybe GP will go a step farther and also mandate arrays that return elements in random order too. Relying on insertion order for any reason is for weaklings.
Re: Why is Python's OrderedDict ordered?
#9Earlier quoted context omitted.
I'd love to see the results of mandating a random order dict impl at an actual company/org (but hate to be forced to participate). Hopefully you hired developers who really like to write sorting algos.
Well, that is how hash tables in go works, so you'd not have to look that far.
Perl since 5.8.something has had the option of perturbing the hash function, so it is different from run to run. You can also set the set to a given value in order to lock in the sequence.
In any case, it is not ordered. If you want that, you have to explicitly sort the keys of the hash.
Re: Why is Python's OrderedDict ordered?
#10Earlier quoted context omitted.
I don't think this is the "why". What you're depicting is what happened in JavaScript. Dictionary keys in Python always had that (to me) annoying property that they preserved insertion order until they don't. I'd frankly much prefer if they'd always be iterated in random order each time they're traversed.
I'd love to see the results of mandating a random order dict impl at an actual company/org (but hate to be forced to participate). Hopefully you hired developers who really like to write sorting algos.
Swift (heavily used by Apple) has randomly
ordered dictionaries for
security:
> In particular, random seeding enables better protection against (accidental or deliberate) hash-flooding attacks
https://forums.swift.org/t/psa-the-stdlib-now-uses-randomly-...