How we made Python's packaging library 3x faster

https://iscinumpy.dev/post/packaging-faster/

88•rbanffy•3w ago

Comments

zahlman•3w ago

Previously: https://news.ycombinator.com/item?id=46557542

djoldman•2w ago

> _canonicalize_table = str.maketrans( "ABCDEFGHIJKLMNOPQRSTUVWXYZ_.", "abcdefghijklmnopqrstuvwxyz--", )

> ...

> value = name.translate(_canonicalize_table)

> while "--" in value:

> value = value.replace("--", "-")

translate can be wildly fast compared to some commonly used regexes or replacements.

teaearlgraycold•2w ago

I would expect however that a regex replacement would be much faster than your N^2 while loop.

notpushkin•2w ago

It would be, if it was a common situation.

This loop handles cases like `eggtools._spam` → `eggtools-spam`, which is probably rare (I guess it’s for packages that export namespaced modules, and you probably don’t want to export _private modules; sorry in advance for non-pythonic terminology). Having more than two separator characters in a row is even more unusual.

dgrunwald•2w ago

That loop isn't N²: if there are long sequences of dashes, every iteration will cut the lengths of those sequences in half. So the loop has at most lg(N) iterations, for a O(N*lg(N)) total runtime.

est•2w ago

I am curious, why not .lower().translate('_.', '--')

fwip•2w ago

.lower() has to handle Unicode, right? I imagine the giant tables slow it down a bit.

mort96•2w ago

It's so annoying how so many languages lack a basic "ASCII lowercase" and "ASCII uppercase" function. All the Unicode logic is not only unnecessary, but actively unwanted, when you e.g want to change the case of a hex encoded string or do normalization on some machine generated ASCII-only output.

tracker1•2w ago

I'll say, C#'s .ToLowerInvariant, etc. are pretty nice when you need them.

est•2w ago

> It's so annoying how so many languages lack a basic "ASCII lowercase" and "ASCII uppercase" function

How about b''.lower() ?

mort96•2w ago

What if I have a string and not a byte string?

ltbarcly3•2w ago

Misleading title, they didn't make the packaging library 3x faster, they made reading one attribute of a package 3x faster. The whole library is still very, very slow compared to alternatives.

imtringued•2w ago

Unrelated, but I personally am not satisfied with the performance of Panda's XLSX export. As you can see here [0], the code does really strange things. It takes cell.style and throws it into json.dumps() to generate a key for a dictionary so that they can cache the XlsxStyler.convert(cell.style) result. Except, the vast majority of cells do not have any styling whatsoever, so json.dumps is producing the string "null", which is then used to lookup None. The low hanging fruit are jaw dropping. You can easily speed up the code 10%+ by adding a simple check "if cell.style is not None or fmt is not None:" and switching from json.dumps(cell.style) to str(cell.style). If I wanted an easy weekend project that positively impacts many people this is what I'd work on.

[0] https://github.com/pandas-dev/pandas/blob/main/pandas/io/exc...

rthz•2w ago

Have you tried opening an issue about it? Maybe someone would be happy to work on it. I concur that Excel parsing is rather slow.

Make a local open-source AI chatbot with access to Fedora documentation

Introduce the Vouch/Denouncement Contribution Model by Mitchellh

Software Factories and the Agentic Moment

The Neuroscience Behind Nutrition for Developers and Founders

Bang bang he murdered math {the musical } (2024)

A Night Without the Nerds – Claude Opus 4.6, Field-Tested

Could ionospheric disturbances influence earthquakes?

SpaceX's next astronaut launch for NASA is officially on for Feb. 11 as FAA clea

Show HN: One-click AI employee with its own cloud desktop

Show HN: Poddley – Search podcasts by who's speaking

Same Surface, Different Weight

The Rise of Spec Driven Development

The first good Raspberry Pi Laptop

Seas to Rise Around the World – But Not in Greenland

Will Future Generations Think We're Gross?

State Department will delete Xitter posts from before Trump returned to office

Show HN: Verifiable server roundtrip demo for a decision interruption system

Impl Rust – Avro IDL Tool in Rust via Antlr

Stories from 25 Years of Software Development

minikeyvalue

Neomacs: GPU-accelerated Emacs with inline video, WebKit, and terminal via wgpu

Show HN: Moli P2P – An ephemeral, serverless image gallery (Rust and WebRTC)

How I grow my X presence?

What's the cost of the most expensive Super Bowl ad slot?

What if you just did a startup instead?

Hacking up your own shell completion (2020)

Show HN: Gorse 0.5 – Open-source recommender system with visual workflow editor

GLM-OCR: Accurate × Fast × Comprehensive

Local Agent Bench: Test 11 small LLMs on tool-calling judgment, on CPU, no GPU

Show HN: AboutMyProject – A public log for developer proof-of-work