npyz
Library Featured
NumPy file format (de-)serialization. Fork of outdated npy-rs.
- Downloads
- 467,634
- Dependents
- 36
- Stars
- 33
- Forks
- 11
- Contributors
- 10
- Commits
- 259
- Latest release
- 0.9.1 ·
About
Numpy format (*.npy) serialization and deserialization.
NPY is a simple binary data format.
It stores the type, shape and endianness information in a header,
which is followed by a flat binary data field. This crate offers a simple, mostly type-safe way to
read and write *.npy files. Files are handled using iterators, so they don't need to fit in memory.
npyz is a fork and successor of the seemingly-dead npy.
Usage
[dependencies]
npyz = "0.9"
You also may be interested in enabling some features:
[dependencies]
npyz = {version = "0.9", features = ["derive", "complex", "npz", "arrayvec", "half"]}
Data can now be read from a *.npy file:
fn main() -> Result<(), Box<dyn std::error::Error>> {
let bytes = std::fs::read("test-data/plain.npy")?;
// Note: In addition to byte slices, this accepts any io::Read
let npy = npyz::NpyFile::new(&bytes[..])?;
for number in npy.data::<f64>()? {
let number = number?;
eprintln!("{}", number);
}
Ok(())
}
For further examples and information on:
- Reading
npyfiles, - Writing
npyfiles, - Working with structured arrays,
- Interop with the
ndarraycrate, - NPZ files and scipy sparse matrices,
Read the full README
please see the documentation on the root module.
Relation to similar crates
The name npyz is actually an abbreviation. Here is the full name of the crate:
npyplus npz support, and a lot of other features that are frankly a lot more important than npz—not to mention the fact that npz support isn't even actually included in the first release—but I had to call it something, okay
To clarify, npyz is a fork of Pavel Potoček's npy crate. The original npy supported structured arrays with derives, but had many, many limitations.
Compared to npy, npyz has:
- Support for multidimensional arrays.
- Support for big endian files.
- Support for
Complex, strings and bytestrings. - A more versatile reading API based on
std::io::Read, so you can read directly from e.g. azip::read::ZipFile. The original API required a&[u8], with the expectation that a user can use a memmap for large files. - Writing APIs based on
std::io::Write.
Originally, nippynpyz was a place for me to protype new features with reckless abandon before finally making a PR to npy, but even my first few foundational PRs have yet to be merged upstream. I believe Pavel has a good head on their shoulders and a great attention to detail, and I appreciated their initial response on my PRs, but nearly two years have passed since the last time I have heard from them. Therefore, I've decided to go forward and publish the fork.
License
npyz is Copyright 2021 Michael Lamparski, and provided under the terms of the MIT License.
npyz is based off of npy. npy is Copyright 2018 Pavel Potoček, which was provided under the terms of the MIT License.
Compatibility
- Runs on
- GPU support unknown
What shows it
- no dependency or feature matches a backend row
- Native code
- None found
- No native code found
- Python bindings
- No Python binding crate found
- License
- MIT
Compare with similar projects
Order: strongest tier first, then most downloads, then name, with unmeasured values last. A library counts downloads over 30 days. An app counts binary downloads per release. An app with none counts its crate downloads over 30 days. ML Rust runs this catalogue, so its closest project always gets a row.
| Project | Downloads | Dependents | Stars | Latest release | Runs on (GPU) | Native code | License |
|---|---|---|---|---|---|---|---|
|
NumPy file format (de-)serialization. Fork of outdated npy-rs. |
467,634 downloads over 30 days | 36 | 33 | 0.9.1 | GPU support unknown | No native code found | MIT |
|
lance Featured
A columnar data format that is 100x faster than Parquet for random access. |
915,526 downloads over 30 days | 48 | 7,268 | 14.0.2 | GPU support unknown | Binds native code: ring (feature credential-vendor-gcp), lz4-sys (feature lz4), zstd-sys (feature zstd). Build uses a native toolchain: cc | Apache-2.0 |
|
ndarray-npy Featured
.npy and .npz file format support for ndarray |
560,950 downloads over 30 days | 99 | 71 | 0.10.0 | GPU support unknown | No native code found | Apache-2.0 OR MIT |
|
zarrs Featured
A library for the Zarr storage format for multidimensional arrays and metadata |
75,052 downloads over 30 days | 51 | 285 | 0.23.14 | GPU support unknown | Binds native code: blosc-src (feature blosc), gdeflate-sys (feature gdeflate), zfp-sys (feature zfp), zstd-sys (feature zstd) | Apache-2.0 OR MIT |
|
vortex Listed
An extensible, state-of-the-art framework for columnar compression, and the fastest FOSS columnar file format. Formerly at @spiraldb, now an Incubation Stage project at LFAI&Data, part of the Linux Foundation. |
98,129 downloads over 30 days | 32 | 3,310 | 0.93.0 | GPU support unknown | Binds native code: zstd-sys | Apache-2.0 |
|
hdf5-pure-rs New
Pure Rust implementation of the HDF5 file format |
801 downloads over 30 days | 5 | 5 | 0.3.10 | GPU support unknown | No native code found | BSD-3-Clause |
|
Model conversion and quantization with no Python: reads SafeTensors, GGUF, TCF and PyTorch state dicts, writes SafeTensors, GGUF and TCF, and quantizes to Q2_K through Q8_0 and IQ4 formats, including Q4_K_M mixes. GPTQ, AWQ, NF4, FP8, EXL2 and ONNX input are not implemented. Python bindings |
23 downloads over 30 days | Not applicable | 0 | 0.2.1 | GPU support unknown | No native code found | Apache-2.0 |
Why FeaturedIt passes every Featured gate.
What it meets
- It has 32 active dependents and 28 new dependents in 365 days. Featured needs 11 active dependents or 9 new dependents in 365 days.
- Active dependents are at 100% of their peak. Featured needs at least 50%.
- Docs are present. The release commit or a manifest ties the crate to the repository.
- No vulnerability advisory stays unpatched past the grace window. At least one version is neither a prerelease nor 0.0.x.
- The last activity is on 3 May 2026, 190 days ago. The rules expect an update within 1200 days. Dormancy rule
Exact rules: Featured library. The check on applied thresholds version 9.
Every rule outcome, as the check records it
expected-interval: version 0.9.1 base 300, doubled for 467634 downloads per month, doubled for 32 active users: E = 1200 daysdormancy: last activity 2026-05-03, 190 days ago, E = 1200: activefeatured: featured: active_users 32, new_adopters 28, former_glory 1
Measurements and sources
Each signal row shows the raw value, its source and the fetch date. The Sources list gathers every distinct source on this page. Movement needs more history.
Sources6 sources
- Description: the crates.io description
- crates.io database dump, fetched
- RustSec advisory database, fetched
- GitHub repository, fetched
- crates.io package, fetched
- GitHub contributors, fetched
Adoption32 active dependents, 28 new dependents in 365 days1 not measured
| Signal | Value | Source | Fetched | Counts |
|---|---|---|---|---|
| Active dependents | 32 | crates.io database dump | Yes | |
| New dependents (365 days) | 28 | crates.io database dump | Yes | |
| Peak active dependents | 31.5 | crates.io database dump | Yes | |
| Active dependents as a share of the peak | 1 | crates.io database dump | Yes | |
| Binary downloads per release | Not measured | Yes |
MaintenanceLatest human commit: 6 months ago3 not measured
| Signal | Value | Source | Fetched | Counts |
|---|---|---|---|---|
| Latest human commit | 2026-05-03 | GitHub repository | Yes | |
| Latest release | 2026-05-02 | crates.io database dump | Yes | |
| First release | 2021-07-02 | crates.io database dump | Yes | |
| Latest version | 0.9.1 | crates.io database dump | Yes | |
| Days the oldest outside issue waits for a reply | 67 | GitHub repository | Yes | |
| Maintainer replies over 365 days | 29 | GitHub repository | Yes | |
| Repository archived | false | GitHub repository | Yes | |
| Repository gone | false | GitHub repository | Yes | |
| Release commit or manifest in the repo | true | crates.io package | Yes | |
| Published docs | true | crates.io database dump | Yes | |
| Latest release fails cargo check | Not measured | Yes | ||
| Build check date | Not measured | Yes | ||
| Build check toolchain | Not measured | Yes |
SecurityUnpatched vulnerabilities: none
| Signal | Value | Source | Fetched | Counts |
|---|---|---|---|---|
| Unpatched vulnerabilities past the grace window | none | RustSec advisory database | Yes | |
| RustSec unmaintained advisory | none | RustSec advisory database | Yes | |
| Deprecation notice | none | crates.io database dump | Yes | |
| Deprecated requirement | none | crates.io database dump | Yes |
Distribution15 releases, 467,634 downloads over 30 days5 not measured
| Signal | Value | Source | Fetched | Counts |
|---|---|---|---|---|
| Releases | 15 | crates.io database dump | Yes | |
| Downloads over 30 days | 467634 | crates.io database dump | Yes | |
| Binary downloads over the last 3 releases | Not measured | Yes | ||
| Homebrew installs on request over 365 days | Not measured | Yes | ||
| Repology repository families | Not measured | Yes | ||
| Docker pull growth over 90 days | Not measured | Yes | ||
| Docker pulls at the growth baseline | Not measured | Yes | ||
| Every version a prerelease | false | crates.io database dump | Yes | |
| Every version 0.0.x | false | crates.io database dump | Yes | |
| Every version yanked | false | crates.io database dump | Yes | |
| Crate deleted from crates.io | false | crates.io database dump | Yes |
Repository33 stars, 11 forks, 10 contributors, 259 commits. Stars alone never qualify a project.
| Signal | Value | Source | Fetched | Counts |
|---|---|---|---|---|
| GitHub stars | 33 | GitHub repository | Yes — one part of the repository route | |
| GitHub forks | 11 | GitHub repository | Yes — one part of the repository route | |
| Contributors with a GitHub account | 10 | GitHub contributors | Yes — one part of the repository route | |
| Commits on the default branch | 259 | GitHub repository | No | |
| Repository's main crate left out of the entry | none | crates.io database dump | Yes |
Facts that never count
| Signal | Value | Source | Fetched | Counts |
|---|---|---|---|---|
| License | MIT | crates.io database dump | No | |
| Runs on, from listed crates and their direct dependencies | GPU support unknown | crates.io database dump | No | |
| What shows each backend | no dependency or feature matches a backend row | crates.io database dump | No | |
| Native code, from listed crates and their dependencies | No native code found | crates.io database dump | No | |
| Python bindings, from direct dependencies of listed crates | No Python binding crate found | crates.io database dump | No | |
| Crates that depend on a listed crate directly | 36 | crates.io database dump | No |
Corrections and review history
No correction applies to this entry.
Judgments
A judgment enters only through an approved issue and a merged pull request.
No judgment applies to this entry.