bitarray

efficient arrays of booleans -- C extension

bitarray Permissive license PSF-2.0 Active ★ 792 v3.10.1 released 2026-08-07

Install

bitarray on PyPI

pip

pip install bitarray

uv

uv add bitarray

poetry

poetry add bitarray

Package facts

License	PSF-2.0 (permissive)
Python support	supports the current Python release (>=3.7)
Install friction	medium — platform-specific wheel
Runtime dependencies	none
Maintenance	actively maintained — 6 days since the last release
Last repo commit	2026-08-13
First released	2008-08-17
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: bitarray-3.10.1-cp310-cp310-macosx_10_9_x86_64.whl; bitarray-3.10.1-cp310-cp310-macosx_11_0_arm64.whl; bitarray-3.10.1-cp310-cp310-manylinux2014_aarch64.manylinux_2_17_aarch64.manylinux_2_28_aarch64.whl; bitarray-3.10.1-cp310-cp310-manylinux2014_ppc64le.manylinux_2_17_ppc64le.manylinux_2_28_ppc64le.whl; bitarray-3.10.1-cp310-cp310-manylinux2014_s390x.manylinux_2_17_s390x.manylinux_2_28_s390x.whl; bitarray-3.10.1-cp310-cp310-manylinux2014_x86_64.manylinux_2_17_x86_64.manylinux_2_28_x86_64.whl; bitarray-3.10.1-cp310-cp310-musllinux_1_2_aarch64.whl; bitarray-3.10.1-cp310-cp310-musllinux_1_2_ppc64le.whl; bitarray-3.10.1-cp310-cp310-musllinux_1_2_s390x.whl; bitarray-3.10.1-cp310-cp310-musllinux_1_2_x86_64.whl; bitarray-3.10.1-cp310-cp310-win32.whl; bitarray-3.10.1-cp310-cp310-win_amd64.whl; bitarray-3.10.1-cp310-cp310-win_arm64.whl; bitarray-3.10.1-cp311-cp311-macosx_10_9_x86_64.whl; bitarray-3.10.1-cp311-cp311-macosx_11_0_arm64.whl; bitarray-3.10.1-cp311-cp311-manylinux2014_aarch64.manylinux_2_17_aarch64.manylinux_2_28_aarch64.whl; bitarray-3.10.1-cp311-cp311-manylinux2014_ppc64le.manylinux_2_17_ppc64le.manylinux_2_28_ppc64le.whl; bitarray-3.10.1-cp311-cp311-manylinux2014_s390x.manylinux_2_17_s390x.manylinux_2_28_s390x.whl; bitarray-3.10.1-cp311-cp311-manylinux2014_x86_64.manylinux_2_17_x86_64.manylinux_2_28_x86_64.whl; bitarray-3.10.1-cp311-cp311-musllinux_1_2_aarch64.whl

Development Status :: 6 - MatureIntended Audience :: DevelopersOperating System :: OS IndependentProgramming Language :: CProgramming Language :: Python :: 3Programming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.14Programming Language :: Python :: 3.7Programming Language :: Python :: 3.8Programming Language :: Python :: 3.9Programming Language :: Python :: Free Threading :: 2 - BetaTopic :: Utilities

About bitarray

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

bitarray: efficient arrays of booleans

This library provides an object type which efficiently represents an array of booleans. Bitarrays are sequence types and behave very much like usual lists. Eight bits are represented by one byte in a contiguous block of memory. The user can select between two representations: little-endian and big-endian. All functionality is implemented in C. Methods for accessing the machine representation are provided, including the ability to import and export buffers. This allows creating bitarrays that are mapped to other objects, including memory-mapped files.

Key features

The bit-endianness can be specified for each bitarray object, see below.
Sequence methods: slicing (including slice assignment and deletion), operations +, *, +=, *=, the in operator, len()
Bitwise operations: ~, &, |, ^, <<, >> (as well as their in-place versions &=, |=, ^=, <<=, >>=).
Free-threading support (for GIL disabled CPython 3.14 and later)
Fast methods for encoding and decoding variable bit length prefix codes.
Bitarray objects...

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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

bitarray provides an efficient, memory-compact array type for storing sequences of boolean values, with support for bitwise operations, slicing, and buffer protocol access—all implemented in C for performance.

Medium install friction due to compiled C extension; however, pre-built wheels cover all major platforms (x86_64, ARM, s390x, ppc64le) and Python versions 3.7–3.14, so installation typically succeeds without compilation. Active maintenance (6 days since last release) and 792 repository stars indicate solid upkeep.

Licensed under PSF-2.0, a permissive license compatible with both commercial and open-source use with minimal restrictions.

Usage

pip install bitarray

from bitarray import bitarray
a = bitarray()
a.append(1)
a.extend([1, 0])
print(a.count(1))

Requires Python 3.7 or later; C extension compilation may be needed on platforms without pre-built wheels.

Verdict: bitarray is a mature, actively maintained library (first released 2008-08-17, latest release 2026-08-07) with zero known vulnerabilities and broad platform coverage. Its C implementation and permissive PSF-2.0 license make it a reliable choice for performance-critical boolean array operations. Install friction is moderate but manageable given comprehensive wheel availability.

Needs verification

Whether the free-threading support (GIL-disabled CPython 3.14+) mentioned in classifiers is production-ready or experimental.
Performance characteristics and typical use cases where bitarray outperforms alternative approaches.

efficient boolean arraybitwise operations pythonmemory-efficient bit storageboolean sequence typebit manipulation librarycompact binary databitarray data structure