preshed

Cython hash table that trusts the keys are pre-hashed

preshed Permissive license MIT Active ★ 88 v3.0.13 released 2026-03-23

Install

preshed on PyPI

pip

pip install preshed

uv

uv add preshed

poetry

poetry add preshed

Package facts

License	MIT (permissive)
Python support	supports the current Python release (<3.15,>=3.9)
Install friction	medium — platform-specific wheel
Runtime dependencies	2 — cymem, murmurhash
Maintenance	actively maintained — 143 days since the last release
Last repo commit	2026-03-27
First released	2014-09-26
Popularity	one of the top 1,000 most-downloaded packages on PyPI (30-day window, as of 2026-08-13)
Known vulnerabilities	none known (OSV.dev, checked 2026-08-13)

Evidence: preshed-3.0.13-cp310-cp310-macosx_10_9_x86_64.whl; preshed-3.0.13-cp310-cp310-macosx_11_0_arm64.whl; preshed-3.0.13-cp310-cp310-manylinux2014_aarch64.manylinux_2_17_aarch64.whl; preshed-3.0.13-cp310-cp310-manylinux2014_x86_64.manylinux_2_17_x86_64.whl; preshed-3.0.13-cp310-cp310-musllinux_1_2_aarch64.whl; preshed-3.0.13-cp310-cp310-musllinux_1_2_x86_64.whl; preshed-3.0.13-cp310-cp310-win_amd64.whl; preshed-3.0.13-cp310-cp310-win_arm64.whl; preshed-3.0.13-cp311-cp311-macosx_10_9_x86_64.whl; preshed-3.0.13-cp311-cp311-macosx_11_0_arm64.whl; preshed-3.0.13-cp311-cp311-manylinux2014_aarch64.manylinux_2_17_aarch64.whl; preshed-3.0.13-cp311-cp311-manylinux2014_x86_64.manylinux_2_17_x86_64.whl; preshed-3.0.13-cp311-cp311-musllinux_1_2_aarch64.whl; preshed-3.0.13-cp311-cp311-musllinux_1_2_x86_64.whl; preshed-3.0.13-cp311-cp311-win_amd64.whl; preshed-3.0.13-cp311-cp311-win_arm64.whl; preshed-3.0.13-cp312-cp312-macosx_10_13_x86_64.whl; preshed-3.0.13-cp312-cp312-macosx_11_0_arm64.whl; preshed-3.0.13-cp312-cp312-manylinux2014_aarch64.manylinux_2_17_aarch64.whl; preshed-3.0.13-cp312-cp312-manylinux2014_x86_64.manylinux_2_17_x86_64.whl

Environment :: ConsoleIntended Audience :: DevelopersIntended Audience :: Science/ResearchLicense :: OSI Approved :: MIT LicenseOperating System :: MacOS :: MacOS XOperating System :: Microsoft :: WindowsOperating System :: POSIX :: LinuxProgramming Language :: CythonProgramming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.14Programming Language :: Python :: 3.9Programming Language :: Python :: Free Threading :: 2 - BetaTopic :: Scientific/Engineering

About preshed

from the package's own PyPI description — quoted content, verbatim

preshed: Cython Hash Table for Pre-Hashed Keys

Simple but high performance Cython hash table mapping pre-randomized keys to void* values. Inspired by Jeff Preshing.

All Python APIs provded by the BloomFilter and PreshMap classes are thread-safe on both the GIL-enabled build and the free-threaded build of Python 3.14 and newer. If you use the C API or the PreshCounter class, you must provide external synchronization if you use the data structures by this library in a multithreaded environment.

tests (image) pypi Version (image) conda Version (image) [![Python...

Read as markdown · JSON record · Source repository · Homepage

AI interpretation — verify before relying

AI-generated interpretation of the package facts above; every digit, version, license, or vulnerability id it cites is grounded in the facts already shown on this page

preshed provides high-performance Cython hash tables and probabilistic data structures (PreshMap, BloomFilter, PreshCounter) for fast lookups and counting of pre-hashed integer keys, with thread-safe Python APIs and low-level C access.

Medium install friction due to compiled Cython wheels, but well-mitigated by extensive platform coverage (macOS, Linux, Windows; ARM and x86_64) across Python 3.10–3.14. Active maintenance with recent release (143 days ago) and no known vulnerabilities.

MIT license permits unrestricted commercial and private use, modification, and distribution with minimal restrictions—a permissive choice well-suited to library adoption.

Usage

pip install preshed

from preshed.maps import PreshMap
map = PreshMap()
map[key] = value
value = map[key]

Requires Python 3.9–3.14; pre-built wheels available for common platforms, but source build requires Cython and a C compiler.

Verdict: preshed is a mature, actively maintained library with no security issues, permissive licensing, and broad platform support. Medium install friction is offset by pre-built wheels and a stable maintenance track record. Suitable for production use in data-intensive applications requiring fast integer-key lookups.

Needs verification

Whether cymem and murmurhash dependencies introduce additional install or runtime constraints beyond wheel distribution.
Performance characteristics and memory overhead compared to standard alternatives in typical workloads.

cython hash tablefast key-value storebloom filter implementationpre-hashed key mappinghigh performance counterinteger key hashingthread-safe hash map