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Title 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 withou
by addaon 1y ago
Title 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.)
- DemocracyFTW2 1y agoI 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.
- not_kurt_godel 1y agoI'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.
- yxhuvud 1y agoWell, that is how hash tables in go works, so you'd not have to look that far.
- not_kurt_godel 1y agoGreat. 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.
- tasty_freeze 1y agoPerl 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.
- nielsbot 1y agoSwift (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-seeded-hash-values/10789 https://forums.swift.org/t/psa-the-stdlib-now-uses-randomly-...
- not_kurt_godel 1y agoPerhaps not unrelated to why Python is the #1 most popular language while Swift is #22 https://www.tiobe.com/tiobe-index/ https://www.tiobe.com/tiobe-index/
- nielsbot 1y agoSwift isn’t popular because its Dictionary type uses randomly ordered keys?
- cyanydeez 1y agoProbably the inference is YAGNI .
- not_kurt_godel 1y agoIt certainly could be a reason among many. Just look at the thread GP shared, containing multiple years' worth of users voicing frustration at the introduction of this behavior.
- recursivecaveat 1y agoI was under that impression as well, but it was added as an implementation in 3.6 (https://bugs.python.org/issue27350 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 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?
- snthpy 1y agoThanks, How makes much more sense. The post title is dumb. Why is Hackernews news for hackers?
- bradchoate 1y agoThe URL for the post includes "why" (en-why-is-python-ordereddict-ordered), so I suppose the title of the article was updated after the HN post was created. The site's native language is Chinese and I'm guessing the post was translated via automation. In fact, if you run the article through an automated translation service (Google Translate), it reproduces the "Why" title.
- snthpy 1y agoThanks, makes sense.
- more_corn 1y ago^ came here to say exactly this