TOtosh·Mar 6, 2023Submission
ciso8601: Fast ISO8601 date time parser for Python written in C
3 points · Open discussioncloseio
ciso8601
Python2014–2023
closeio / ciso8601
ciso8601
Fast ISO8601 date time parser for Python written in C
4Distinct people
6Mentions
0Explicit recommenders
578GitHub stars
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What it is
Fast ISO8601 date time parser for Python written in C
GitHub
Where it is used
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This week on Hacker News
Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 3:56:07 PM UTC.
No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.
Mentions over time
HN mentions by year6 dated mentions
Observed mentions: 2014-06-10 03:19:24 UTC to 2023-03-06 13:11:33 UTC.
Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.
View mention counts and date ranges
| Period | Start (UTC) | End (exclusive, UTC) | Mentions | Submissions | Comments |
|---|---|---|---|---|---|
| 2014 | 2014-01-01 00:00:00 UTC | 2015-01-01 00:00:00 UTC | 3 | 0 | 3 |
| 2015 | 2015-01-01 00:00:00 UTC | 2016-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2016 | 2016-01-01 00:00:00 UTC | 2017-01-01 00:00:00 UTC | 1 | 0 | 1 |
| 2017 | 2017-01-01 00:00:00 UTC | 2018-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2018 | 2018-01-01 00:00:00 UTC | 2019-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2019 | 2019-01-01 00:00:00 UTC | 2020-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2020 | 2020-01-01 00:00:00 UTC | 2021-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2021 | 2021-01-01 00:00:00 UTC | 2022-01-01 00:00:00 UTC | 0 | 0 | 0 |
| 2022 | 2022-01-01 00:00:00 UTC | 2023-01-01 00:00:00 UTC | 1 | 0 | 1 |
| 2023 | 2023-01-01 00:00:00 UTC | 2024-01-01 00:00:00 UTC | 1 | 1 | 0 |
What Hacker News says
6 sourcesI see your point, but it directly conflicts with the effort many people put into producing extremely fast libraries for specific purposes, such as web frameworks (benchmarked extensively), ORMs and things like json and date parsing, as seen in the excellent ciso8601 [1] for example.
[1] https://github.com/closeio/ciso8601
In Python 3.11 vs 3.10 performanceI had similar issues in Python, where the available date parsers weren't fast enough.
With my C module, I got 320ns, which was 62x faster than Python's less flexible strptime. See https://github.com/closeio/ciso8601/ for my benchmarks.
In Timing the time it takes to parse timeI did all the timeit benchmarks on the latest 13" retina MacBook Pro, 2.6 GHz Intel Core i5. The profiler screenshot is from one of our serves on EC2.
Of course there is always potential for optimization, but at this point it's fast enough for our purposes. If you can make it significantly faster please don't hesitate to submit a PR though :)
EDIT: Wouldn't most C compilers unroll the simple "for" loops? Direct link to the C code: https://github.com/elasticsales/ciso8601/blob/master/module....
In Show HN: A fast ISO8601 date-time parser for PythonGood idea with the regex, haven't tried it. That being said, you didn't take the time into account to construct a datetime object, let alone attach time zone information. ciso8601 supports time zones using pytz' FixedOffset and UTC classes, see https://github.com/elasticsales/ciso8601 for additional benchmarks. There's potential for further speedup by using a tzoffset subclass written in C, but in our cases all dates were UTC anyway and so we didn't need the time zone.
In Show HN: A fast ISO8601 date-time parser for PythonYou can see the issue it solves pretty clearly here: https://github.com/elasticsales/ciso8601#benchmark
Python != PHP
In Show HN: A fast ISO8601 date-time parser for Python