# h5py/h5py

HDF5 for Python -- The h5py package is a Pythonic interface to the HDF5 binary data format.

Repository: https://github.com/h5py/h5py
Canonical: https://ross.abutalabs.com/products/h5py
Homepage: http://www.h5py.org
Language: Python
License: BSD-3-Clause
License Family: permissive
Last push: 2026-08-21T13:49:49+00:00

## Health v2 (maintenance only)
Score: 81/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 98, release rhythm 49, longevity 100
- inputs: {"age_days": 5095, "days_push": 12, "days_rel": 180, "gap_med": 117.5, "n_releases_24m": 7}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 2249, forks 564 (observed 2026-08-28T04:06:30.860617+00:00)

## What it is
h5py is a Pythonic wrapper around the HDF5 binary data format, built on a Cython binding of the HDF5 C API. It lets you store and manipulate huge amounts of numerical data from NumPy, including slicing multi-terabyte datasets on disk as if they were in-memory arrays.

## Use cases
- store large numerical datasets in HDF5 files from Python
- read and slice multi-terabyte datasets on disk like NumPy arrays
- exchange scientific data with MATLAB or IDL users
- organize thousands of datasets in a single tagged file
- access low-level HDF5 C API features from Python
- work with HDF5 files with MPI parallel support

## When to choose
- you need to persist large NumPy arrays or hierarchical numerical data in a standard binary format
- you want out-of-core access to datasets too big for memory
- you need interoperability with other HDF5 tools like MATLAB, IDL, or PyTables

## When to avoid
- you only need simple tabular data where CSV, Parquet, or SQLite suffice
- you need a database with querying and indexing rather than a file format
- you work outside the Python/NumPy ecosystem and can use the HDF5 C library directly

## Facets
- artifact type: library
- maturity: stable
- function: serialization, file-system, data-science
- domain: data-science, files, developer-tools
- platform: python, cross-platform, windows
- tags: hdf5, numpy, binary-data-format, scientific-computing, large-datasets, linux, macos

## Member repositories
- h5py/h5py (main) score 81

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:06:30.860617+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-30T02:43:54.710161+00:00, confidence not recorded.
  - readme: https://github.com/h5py/h5py (fetched 2026-08-28T04:06:30.860617+00:00, sha 06bfb8ef3304)
  - homepage: http://www.h5py.org (fetched 2026-08-29T10:25:55.580057+00:00, sha ccf773c9add7)
- Data as of 2026-08-30T08:39:29.467469+00:00.