Change log

3.8.1 (2026-04-02):

• fixed critial findings in C Extension Analysis Report, see #250
• add tests, in particular devel/test_capi.py

3.8.0 (2025-11-02):

• add experimental support for free-threaded builds (GIL disabled), #234
• remove _set_default_endian()
• add .__bytes__(), see #246

3.7.2 (2025-10-08):

• enable util.random_k() for all supported Python versions, previously this functions required Python 3.9 or higher
• add official Python 3.14 support
• update cibuildwheel to 3.2.0

3.7.1 (2025-08-28):

• fix type hinting for memoryviews, see #241
• add bit-endianness documentation
• improve testing, including debug mode test for digit_to_int()

3.7.0 (2025-08-24):

• add util.gen_primes(), generate bitarrays in which active indices are prime numbers
• improve .buffer_info() to return named tuple
• add optional mode argument to util.sum_indices() to sum square of active indices
• improve internal _sysinfo() to include Py_DEBUG
• add Dubner's conjecture (in memory of Harvey Dubner)
• add dynamically growing sieve

3.6.1 (2025-08-12):

• add development files for statistical tests in devel/random/
• optimize util.sum_indices()
• fix RecursionError in util.random_k(), see #239
• add devel/test_sum_indices.py

3.6.0 (2025-07-29):

• add util.random_k(), see #237
• add util.sum_indices()
• optimize util.xor_indices()
• move development files from examples/ to devel/

3.5.2 (2025-07-21):

• optimize util.random_p() by also using bitwise AND in final step
• fix DeprecationWarning regarding u type code
• add verification tests for internals of util.random_p()

3.5.1 (2025-07-14):

• optimize util.random_p() for n < 100
• add Random Bitarrays documentation
• add statistical tests for random functions

3.5.0 (2025-07-06):

• add util.random_p()
• improve sparse compression testing

3.4.3 (2025-06-23):

• minor updates to documentation

• C-level:

  • simplify and speedup extend_unicode01()
  • customize resize_lite() - avoid unused code
  • use PyTypeObject for bitarray type object in _util.c to be consistent with _bitarray.c
  • add and improve comments to implementation of sparse bitarray compression
  • simplify sc_count()

3.4.2 (2025-05-21):

• extend documentation of compression of sparse bitarrays
• util.sc_decode() and util.vl_decode() now raise StopIteration instead of ValueError when unexpected end of stream is encountered
• add debug mode tests for read_n(), write_n() and count_from_word()

3.4.1 (2025-05-15):

• add pyproject.toml, see #233
• implement bits2bytes() in C
• optimize delslice() when step is larger than about 5
• consistently name *_span() and *_range() in C for invert, set and count
• organize and add tests (including debug mode tests for zlw())

3.4.0 (2025-05-06):

• remove .endian() method in favor of data descriptor .endian
• allow bitarray initializer bytes or bytearray to set buffer directly
• allow calling .extend() with bytes object (although the only valid bytes are 0x00 and 0x01)
• add util.byteswap()
• add util.correspond_all()
• fix .reverse() for imported buffer
• drop Python 3.5 support
• add tests

3.3.2 (2025-05-02):

• fix off-by-one-error in check for length of count argument in util.canonical_decode()
• simplify util.int2ba()
• add tests
• add masked indexing example
• add tricks example

3.3.1 (2025-04-04):

• remove License classifier in favor of a SPDX license expression, #231
• reorganize and cleanup many tests

3.3.0 (2025-03-30):

• add optional group and sep arguments' to .to01(), #230 - as well as util.ba2hex() and util.ba2base()
• ignore whitespace in util.base2ba() and util.hex2ba()
• check for embedded nul characters when extending (and initializing) bitarray from string
• improve testing
• add double precision floating point number example

3.2.0 (2025-03-19):

• add util.xor_indices(), #229
• add Hamming code example

3.1.1 (2025-03-06):

• updated pythoncapi_compat.h for pypy3.11 support, see #227
• use __builtin_parityll() when available in util.parity()
• add parity_64() to header
• simplify some tests
• add LFSR example

3.1.0 (2025-02-19):

• allow mask assignment to bitarrays, see #225
• add missing masked operations to pyi-file
• refactor resize() and avoid overallocation when downsizing buffer
• update build_wheels.yml
• fix some typos
• minor simplifications
• rename growth/ example to resize/ and add tests for resize()
• update gene example
• add comments

3.0.0 (2024-10-15):

• see Bitarray 3 transition
• remove Python 2.7 support
• .decode() now returns iterator (equivalent to past .iterdecode())
• .search() now returns iterator (equivalent to past .itersearch())
• remove .iterdecode() and .itersearch()
• remove util.rindex(), use .index(..., right=1) instead, deprecated since 2.9
• remove util.make_endian(), use bitarray(..., endian=...) instead, deprecated since 2.9
• remove hackish support for bitarray() handling unpickling, see detailed explaination in #207 - closes #206

2.9.3 (2024-10-10):

• add official Python 3.13 support
• update cibuildwheel to 2.21.3
• minor simplifications
• fix some typos

2.9.2 (2024-01-01):

• optimize initialization from strings by not constantly resizing buffer
• optimize util.hex2ba() and util.base2ba() by avoiding unnecessary copies
• optimize util.base2ba() and util.ba2base() for n=16 (hexadecimal)

2.9.1 (2023-12-23):

• avoid buffer being unnecessarily initialized with 0s in several functions of the bitarray.util module
• fix .count() type hint in pyi-file
• improve testing

2.9.0 (2023-12-17):

• deprecate support for Python 2 - Python 2.7 support will be removed in bitarray version 3.0, see roadmap
• bitarray(n) for integer initializer n will always return a bitarray of length n with all items initialized to 0, see #212
• allow sub-bitarray in .count(), #212
• add util.ones()
• .find() and .index(): add keyword argument right for rightmost index
• .itersearch(): add start and stop argument, and keyword argument right (for descending order - starting with rightmost match)
• deprecate util.rindex() (will be removed in 3.0 release), use .index(..., right=True) instead
• deprecate util.make_endian() (will be removed in 3.0 release), use bitarray(..., endian=...) instead

2.8.5 (2023-12-09):

• speedup unaligned copies by always using word shifts (in combination with builtin byte swap 64 when available) when bit-endianness and machine byte-order are opposite
• add HAVE_BUILTIN_BSWAP64 to header
• avoid misaligned pointers when casting to (uint64_t *)
• add tests

2.8.4 (2023-12-04):

• simplify copy_n() (remove special cases), see #d2d6fd53
• add word shift example C program, and simplify shift_r8()
• improve documentation and testing
• add roadmap

2.8.3 (2023-11-11):

• ensure readonly attribute is set correctly when creating new objects, see #211
• optimize sparse bitarray compression for raw block type
• improve hash functions in Bloom filter example

2.8.2 (2023-10-03):

• update cibuildwheel to 2.16.1 in order to provide cp312 wheels on PyPI
• improve error messages for masked assignment
• simplify test collection
• added pytest.ini to allow running pytest with no additional arguments, see #208
• util.sc_encode(): avoid writing empty blocks at end of compressed stream, i.e. skip encoding when total population count is reached

2.8.1 (2023-08-06):

• use reconstructor function for pickling, see #207
• simplify implementation of .reverse()

2.8.0 (2023-07-22):

• allow integer sequence indexing by list of indices, see #204 (addresses #156 and #190)
• add masked indexing by bitarray masks, see #205 (addresses #190)
• improve .bytereverse() docstring, see issue #202

2.7.6 (2023-06-24):

• remove caching hash value, fixes issue #201

2.7.5 (2023-06-10):

• fix for pypy3.9-v7.3.11, #198 (fixes #188)
• enable building wheels for PyPy

2.7.4 (2023-05-29):

• register bitarray as abc.MutableSequence, see #196
• cibuildwheel: update macOS version to 11 from unsupported 10.15, see actions/runner-images#5583
• improve documentation regarding type when indexing single bitarray items, #192

2.7.3 (2023-02-20):

• fix popcount64 name conflict on NetBSD, #189
• even though PyPy is not actively supported, allow running tests for PyPy 3.7 and 3.8, see also #188
• allow running python setup.py test
• add official Python 3.12 support
• simplify count functionality in util module
• retire bitcount_lookup[256] table
• improve util.count_n() error messages
• avoid util module tests from being run more than once in each call to bitarray.test() when called multiple times in the same Python process, see #6e52e49a
• improve testing

2.7.2 (2023-02-12):

• speedup all count functionality by using __builtin_popcountll when available, see #187
• add popcount64() to bitarray.h - we assume now that uint64_t is always available
• improve testing

2.7.1 (2023-02-10):

• optimize util.sc_encode()

2.7.0 (2023-02-05):

• add util.sc_encode() and util.sc_decode() for compression of sparse bitarrays
• add util.any_and()
• add util.intervals()
• move functionality of the following utility functions entirely to C: hex2ba(), base2ba(), deserialize(), vl_decode(), zeros()
• improve error checking for unpickling
• add distance metrics example: dice, hamming, jaccard, kulczynski1, rogerstanimoto, russellrao, sokalmichener, sokalsneath, yule
• add example sparse bitarray implementations

2.6.2 (2023-01-01):

• optimize richcompare() for opposite endianness
• improve some docstrings add tests

2.6.1 (2022-12-18):

• add documentation on shift operators, #181
• fix typo in iterable initializer description, #179
• optimize richcompare()

2.6.0 (2022-07-19):

• add data descriptors: .nbytes, .padbits, .readonly
• allow optional endian argument to be None when creating bitarrays
• fix type annotation for canonical_decode(), #178
• frozenbitarray's pad bits are now guaranteed to be zero
• add tests

2.5.1 (2022-05-10):

• optimize .reverse(), see #177
• allow negative (byte) indices in .bytereverse()

2.5.0 (2022-05-04):

• add calculating of canonical Huffman codes util.canonical_huffman() and decoding thereof util.canonical_decode(), see #173
• allow creating "Huffman codes" from frequency maps with a single symbol in util.huffman_code() and util.canonical_huffman(), see #172
• allow bytes-like argument in .frombytes() and .pack() - previously, the arguments were limited to the bytes object, see #174
• allow bytes-like arguments in util.deserialize()
• add official pyodide support
• add DEFLATE decompression example
• optimize .bytereverse()
• optimize delslice() for cases like del a[1:17:2] when a is large
• fix examples/huffman/compress.py to handle files with 0 or 1 characters, see also #172
• add skipIf decorator for skipping tests
• add tests

2.4.1 (2022-03-29):

• improve resize(), see #167
• optimize copy_n() by avoiding loops, #171
• .bytereverse() no longer sets unused pad bits to zero

2.4.0 (2022-03-01):

• enable building wheels for multiple platforms and Python versions using pypa/cibuildwheel, see #165 and #170 (thanks Brian Thorne, @hardbyte)
• use setuptools instead of distutils in setup.py, #168
• add missing type hinting for .count() step argument

2.3.7 (2022-02-21):

• add optional step argument to .count() method, see #162 and #163
• add tests

2.3.6 (2022-02-07):

• add optional value parameter to util.count_n(), see #154 and #161
• determine machine endianness at build time when possible, by using the PY_LITTLE_ENDIAN macro, in order to optimize shift_r8()
• add official Python 3.11 support

2.3.5 (2022-01-07):

• Fixed bug for big-endian systems (such as IBM s390), see #159 and #160
• Pass zip_safe=False to setup(), see #151

2.3.4 (2021-09-12):

• Fix util.ba2int() for frozenbitarrays. A bug was introduced in 2.3.0 as .tobytes() no longer treats pad bits for read-only buffers as zero.
• add tests

2.3.3 (2021-09-05):

• improve some error messages
• add tests

2.3.2 (2021-08-23):

• fix slice assignment for shared buffer with offset case, see #3ba05687 and #73081e98
• add tests (including internal debug mode tests for buffers_overlap())

2.3.1 (2021-08-20):

• fix special shared buffer copy case, see #815c2a11
• add and improve tests

2.3.0 (2021-08-15):

• add optional buffer argument to bitarray() to import the buffer of another object, #141, #146, see also: buffer protocol
• update .buffer_info() to include: a read-only flag, an imported buffer flag, and the number of buffer exports
• add optional start and stop arguments to util.rindex()
• add memory-mapped file example
• ignore underscore (_) in string input, e.g. bitarray('1100_0111')
• add missing type hinting for new .bytereverse() arguments
• fix .extend() type annotations, #145
• avoid .reverse() using temporary memory
• make .unpack(), util.serialize(), util.vl_encode() and .__reduce__() more memory efficient
• add and improve tests

2.2.5 (2021-08-07):

• speedup find_bit() and find_last() using uint64 checking, this means a speedup for .find(), .index(), .search() and util.rindex()
• add optional start and stop arguments to .bytereverse()
• add example to illustrate how unaligned copying works internally
• add documentation
• add tests

2.2.4 (2021-07-29):

• use shift operations to speedup all unaligned copy operations, #142
• expose functionality to Python level only in debug mode for testing
• add and improve tests

2.2.3 (2021-07-22):

• speedup repeat(), #136
• speedup shift operations, #139
• optimize slice assignment with negative step, e.g.: a[::-1] = 1
• add tests

2.2.2 (2021-07-16):

• speedup slice assignment, see #132 and #135
• speedup bitwise operations, #133
• optimize getbit() and setbit() in bitarray.h
• fix TypeError messages when bitarray or int (0, 1) are expected (bool is a subclass of int)
• add and improve tests

2.2.1 (2021-07-06):

• improve documentation
• speedup vl_encode()
• bitarray.h: make getbit() always an (inline) function
• add assertions in C code

2.2.0 (2021-07-03):

• add bitarray.util.vl_encode() and bitarray.util.vl_decode() which uses a variable length bitarray format, #131

2.1.3 (2021-06-15):

• Fix building with MSVC / Bullseye, #129

2.1.2 (2021-06-13):

• support type hinting for all Python 3 versions (that bitarray supports, 3.5 and higher currently), fixed #128
• add explicit endianness to two tests, fixes #127

2.1.1 (2021-06-11):

• add type hinting (see PEP 484, 561) using stub (.pyi) files
• add tests

2.1.0 (2021-05-05):

• add .find() method, see #122
• .find(), .index(), .search() and .itersearch() now all except both (sub-) bitarray as well as bool items to be searched for
• improve encode/decode error messages
• add lexicographical permutations example
• add tests

2.0.1 (2021-04-19):

• update documentation
• improve some error messages

2.0.0 (2021-04-14):

• require more specific objects, int (0 or 1) or bool, see #119
• items are always returned as int 0 or 1, #119
• remove .length() method (deprecated since 1.5.1 - use len())
• in .unpack() the one argument now defaults to 0x01 (was 0xff)
• .tolist() now always returns a list of integers (0 or 1)
• fix frozenbitarray hash function, see #121
• fix frozenbitarray being mutable by <<= and >>=
• support sequence protocol in .extend() (and bitarray creation)
• improve OverflowError messages from util.int2ba()
• add hexadecimal example

1.9.2 (2021-04-10):

• update pythoncapi_compat: Fix support with PyPy 3.7, #120
• update readme

1.9.1 (2021-04-05):

• switch documentation from markdown to reStructuredText
• add tests

1.9.0 (2021-04-03):

• add shift operations (<<, >>, <<=, >>=), see #117
• add bitarray.util.ba2base() and bitarray.util.base2ba(), see last paragraph in Bitarray representations
• documentation and tests

1.8.2 (2021-03-31):

• fix crash caused by unsupported types in binary operations, #116
• speedup initializing or extending a bitarray from another with different bit-endianness
• add formatting options to bitarray.util.pprint()
• add documentation on bitarray representations
• add and improve tests (all 291 tests run in less than half a second on a modern machine)

1.8.1 (2021-03-25):

• moved implementation of and hex2ba() and ba2hex() to C-level
• add bitarray.util.parity()

1.8.0 (2021-03-21):

• add bitarray.util.serialize() and bitarray.util.deserialize()
• allow whitespace (ignore space and \n\r\t\v) in input strings, e.g. bitarray('01 11') or a += '10 00'
• add bitarray.util.pprint()
• When initializing a bitarray from another with different bit-endianness, e.g. a = bitarray('110', 'little') and b = bitarray(a, 'big'), the buffer used to be simply copied, with consequence that a == b would result in False. This is fixed now, that is a == b will always evaluate to True.
• add test for loading existing pickle file (created using bitarray 1.5.0)
• add example showing how to jsonize bitarrays
• add tests

1.7.1 (2021-03-12):

• fix issue #114, raise TypeError when incorrect index is used during assignment, e.g. a[1.5] = 1
• raise TypeError (not IndexError) when assigning slice to incorrect type, e.g. a[1:4] = 1.2
• improve some docstrings and tests

1.7.0 (2021-02-27):

• add bitarray.util.urandom()
• raise TypeError when trying to extend bitarrays from bytes on Python 3, i.e. bitarray(b'011') and .extend(b'110'). (Deprecated since 1.4.1)

1.6.3 (2021-01-20):

• add missing .h files to sdist tarball, #113

1.6.2 (2021-01-20):

• use Py_SET_TYPE() and Py_SET_SIZE() for Python 3.10, #109
• add official Python 3.10 support
• fix slice assignment to same object, e.g. a[2::] = a or a[::-1] = a, #112
• add bitarray.h, #110

1.6.1 (2020-11-05):

• use PyType_Ready for all types: bitarray, bitarrayiterator, decodeiterator, decodetree, searchiterator

1.6.0 (2020-10-17):

• add decodetree object, for speeding up consecutive calls to .decode() and .iterdecode(), in particular when dealing with large prefix codes, see #103
• add optional parameter to .tolist() which changes the items in the returned list to integers (0 or 1), as opposed to Booleans
• remove deprecated bitdiff(), which has been deprecated since version 1.2.0, use bitarray.util.count_xor() instead
• drop Python 2.6 support
• update license file, #104

1.5.3 (2020-08-24):

• add optional index parameter to .index() to invert single bit
• fix sys.getsizeof(bitarray) by adding .__sizeof__(), see issue #100

1.5.2 (2020-08-16):

• add PyType_Ready usage, issue #66
• speedup search() for bitarrays with length 1 in sparse bitarrays, see issue #67
• add tests

1.5.1 (2020-08-10):

• support signed integers in util.ba2int() and util.int2ba(), see issue #85
• deprecate .length() in favor of len()

1.5.0 (2020-08-05):

• Use Py_ssize_t for bitarray index. This means that on 32bit systems, the maximum number of elements in a bitarray is 2 GBits. We used to have a special 64bit index type for all architectures, but this prevented us from using Python's sequence, mapping and number methods, and made those method lookups slow.
• speedup slice operations when step size = 1 (if alignment allows copying whole bytes)
• Require equal endianness for operations: &, |, ^, &=, |=, ^=. This should have always been the case but was overlooked in the past.
• raise TypeError when trying to create bitarray from boolean
• This will be last release to still support Python 2.6 (which was retired in 2013). We do NOT plan to stop support for Python 2.7 anytime soon.

1.4.2 (2020-07-15):

• add more tests

• C-level:

  • simplify pack/unpack code
  • fix memory leak in ~ operation (bitarray_cpinvert)

1.4.1 (2020-07-14):

• add official Python 3.9 support
• improve many docstrings
• add DeprecationWarning for bitdiff()
• add DeprecationWarning when trying to extend bitarrays from bytes on Python 3 (bitarray(b'011') and .extend(b'110'))

• C-level:

  • Rewrote .fromfile() and .tofile() implementation, such that now the same code is used for Python 2 and 3. The new implementation is more memory efficient on Python 3.
  • use memcmp() in richcompare() to shortcut EQ/NE, when comparing two very large bitarrays for equality the speedup can easily be 100x
  • simplify how unpacking is handled

• add more tests

1.4.0 (2020-07-11):

• add .clear() method (Python 3.3 added this method to lists)
• avoid over-allocation when bitarray objects are initially created
• raise BufferError when resizing bitarrays which is exporting buffers
• add example to study the resize() function
• improve some error messages
• add more tests
• raise NotImplementedError with (useful message) when trying to call the .fromstring() or .tostring() methods, which have been removed in the last release

1.3.0 (2020-07-06):

• add bitarray.util.make_endian()
• util.ba2hex() and util.hex2ba() now also support little-endian
• add bitarray.get_default_endian()
• made first argument of initializer a positional-only parameter
• remove .fromstring() and .tostring() methods, these have been deprecated 8 years ago, since version 0.4.0
• add __all__ in bitarray/__init__.py
• drop Python 3.3 and 3.4 support

1.2.2 (2020-05-18):

• util.ba2hex() now always return a string object (instead of bytes object for Python 3), see issue #94
• util.hex2ba allows a unicode object as input on Python 2
• Determine 64-bitness of interpreter in a cross-platform fashion #91, in order to better support PyPy

1.2.1 (2020-01-06):

• simplify markdown of readme so PyPI renders better
• make tests for bitarray.util required (instead of warning when they cannot be imported)

1.2.0 (2019-12-06):

• add bitarray.util module which provides useful utility functions
• deprecate bitarray.bitdiff() in favor of bitarray.util.count_xor()
• use markdown for documentation
• fix bug in .count() on 32bit systems in special cases when array size is 2^29 bits or larger
• simplified tests by using bytes syntax
• update smallints and sieve example to use new utility module
• simplified mandel example to use numba
• use file context managers in tests

1.1.0 (2019-11-07):

• add frozenbitarray object
• add optional start and stop arguments to .count() method
• add official Python 3.8 support
• optimize setrange() (C-function) by using memset()
• fix issue #74, bitarray is hashable on Python 2
• fix issue #68, unittest.TestCase.assert_ deprecated
• improved test suite - tests should run in about 1 second
• update documentation to use positional-only syntax in docstrings
• update readme to pass Python 3 doctest
• add utils module to examples

1.0.1 (2019-07-19):

• fix readme to pass twine check

1.0.0 (2019-07-15):

• fix bitarrays beings created from unicode in Python 2
• use PyBytes_* in C code, treating the Py3k function names as default, which also removes all redefinitions of PyString_*
• handle negative arguments of .index() method consistently with how they are treated for lists
• add a few more comments to the C code
• move imports outside tests: pickle, io, etc.
• drop Python 2.5 support

0.9.3 (2019-05-20):

• refactor resize() - only shrink allocated memory if new size falls lower than half the allocated size
• improve error message when trying to initialize from float or complex

0.9.2 (2019-04-29):

• fix to compile on Windows with VS 2015, issue #72

0.9.1 (2019-04-28):

• fix types to actually be types, #29
• check for ambiguous prefix codes when building binary tree for decoding
• remove Python level methods: encode, decode, iterdecode (in favor of having these implemented on the C-level along with check_codedict)
• fix self tests for Python 2.5 and 2.6
• move all Huffman code related example code into examples/huffman
• add code to generate graphviz .dot file of Huffman tree to examples

0.9.0 (2019-04-22):

• more efficient decode and iterdecode by using C-level binary tree instead of a python one, #54
• added buffer protocol support for Python 3, #55
• fixed invalid pointer exceptions in pypy, #47
• made all examples Py3k compatible
• add gene sequence example
• add official Python 3.7 support
• drop Python 2.4, 3.1 and 3.2 support

0.8.3 (2018-07-06):

• add exception to setup.py when README.rst cannot be opened

0.8.2 (2018-05-30):

• add official Python 3.6 support (although it was already working)
• fix description of fill(), #52
• handle extending self correctly, #28
• copy_n(): fast copy with memmove() fixed, #43
• minor clarity/wording changes to README, #23

0.8.1 (2013-03-30):

• fix issue #10, i.e. int(bitarray()) segfault
• added tests for using a bitarray object as an argument to functions like int, long (on Python 2), float, list, tuple, dict

0.8.0 (2012-04-04):

• add Python 2.4 support
• add (module level) function bitdiff for calculating the difference between two bitarrays

0.7.0 (2012-02-15):

• add iterdecode method (C level), which returns an iterator but is otherwise like the decode method
• improve memory efficiency and speed of pickling large bitarray objects

0.6.0 (2012-02-06):

• add buffer protocol to bitarray objects (Python 2.7 only)
• allow slice assignment to 0 or 1, e.g. a[::3] = 0 (in addition to booleans)
• moved implementation of itersearch method to C level (Lluis Pamies)
• search, itersearch now only except bitarray objects, whereas __contains__ excepts either booleans or bitarrays
• use a priority queue for Huffman tree example (thanks to Ushma Bhatt)
• improve documentation

0.5.2 (2012-02-02):

• fixed MSVC compile error on Python 3 (thanks to Chris Gohlke)
• add missing start and stop optional parameters to index() method
• add examples/compress.py

0.5.1 (2012-01-31):

• update documentation to use tobytes and frombytes, rather than tostring and fromstring (which are now deprecated)
• simplified how tests are run

0.5.0 (2012-01-23):

• added itersearch method
• added Bloom filter example
• minor fixes in docstrings, added more tests

0.4.0 (2011-12-29):

• porting to Python 3.x (Roland Puntaier)
• introduced .tobytes() and .frombytes() (.tostring() and .fromstring() are now deprecated)
• updated development status
• added sieve prime number example
• moved project to github: https://github.com/ilanschnell/bitarray

0.3.5 (2009-04-06):

• fixed reference counts bugs
• added possibility to slice assign to True or False, e.g. a[::3] = True will set every third element to True

0.3.4 (2009-01-15):

• Made C code less ambiguous, such that the package compiles on Visual Studio, with all tests passing.

0.3.3 (2008-12-14):

• Made changes to the C code to allow compilation with more compilers. Compiles on Visual Studio, although there are still a few tests failing.

0.3.2 (2008-10-19):

• Added sequential search method.
• The special method __contains__ now also takes advantage of the sequential search.

0.3.1 (2008-10-12):

• Simplified state information for pickling. Argument for count is now optional, defaults to True. Fixed typos.

0.3.0 (2008-09-30):

• Fixed a severe bug for 64-bit machines. Implemented all methods in C, improved tests.
• Removed deprecated methods .from01() and .fromlist().

0.2.5 (2008-09-23):

• Added section in README about prefix codes. Implemented _multiply method for faster __mul__ and __imul__. Fixed some typos.

0.2.4 (2008-09-22):

• Implemented encode and decode method (in C) for variable-length prefix codes.
• Added more examples, wrote README for the examples.
• Added more tests, fixed some typos.

0.2.3 (2008-09-16):

• Fixed a memory leak, implemented a number of methods in C. These include __getitem__, __setitem__, __delitem__, pop, remove, insert. The methods implemented on the Python level is very limit now.
• Implemented bitwise operations.

0.2.2 (2008-09-09):

• Rewrote parts of the README
• Implemented memory efficient algorithm for the reverse method
• Fixed typos, added a few tests, more C refactoring.

0.2.1 (2008-09-07):

• Improved tests, in particular added checking for memory leaks.
• Refactored many things on the C level.
• Implemented a few more methods.

0.2.0 (2008-09-02):

• Added bit-endianness property to the bitarray object
• Added the examples to the release package.

0.1.0 (2008-08-17):

• First official release; put project to http://pypi.python.org/pypi/bitarray/

May 2008:

Wrote the initial code, and put it on my personal web-site: http://ilan.schnell-web.net/prog/