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.
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
&=, |=, ^=,
<<=, >>=).
Fast methods for encoding and decoding variable bit length prefix codes.
Bitarray objects support the buffer protocol (both importing and exporting buffers).
Packing and unpacking to other binary data formats, e.g.
numpy.ndarray.
Pickling and unpickling of bitarray objects.
Immutable frozenbitarray objects which are
hashable
Sequential search
Type hinting
Extensive test suite with about 600 unittests
Utility module bitarray.util:
Python wheels are are available on PyPI for all major platforms and Python versions. Which means you can simply:
.. code-block:: shell-session
$ pip install bitarrayOnce you have installed the package, you may want to test it:
.. code-block:: shell-session
$ python -c 'import bitarray; bitarray.test()'
bitarray is installed in: /Users/ilan/bitarray/bitarray
bitarray version: 3.7.2
sys.version: 3.13.5 (main, Jun 16 2025) [Clang 18.1.8]
sys.prefix: /Users/ilan/miniforge
pointer size: 64 bit
sizeof(size_t): 8
sizeof(bitarrayobject): 80
HAVE_BUILTIN_BSWAP64: 1
default bit-endianness: big
machine byte-order: little
Py_DEBUG: 0
DEBUG: 0
.........................................................................
.........................................................................
................................................................
----------------------------------------------------------------------
Ran 597 tests in 0.165s
OKThe test() function is part of the API. It will return a
unittest.runner.TextTestResult object, such that one can
verify that all tests ran successfully by:
.. code-block:: python
import bitarray
assert bitarray.test().wasSuccessful()As mentioned above, bitarray objects behave very much like lists, so there is not too much to learn. The biggest difference from list objects (except that bitarray are obviously homogeneous) is the ability to access the machine representation of the object. When doing so, the bit-endianness is of importance; this issue is explained in detail in the section below. Here, we demonstrate the basic usage of bitarray objects:
.. code-block:: python
>>> from bitarray import bitarray
>>> a = bitarray() # create empty bitarray
>>> a.append(1)
>>> a.extend([1, 0])
>>> a
bitarray('110')
>>> x = bitarray(2 ** 20) # bitarray of length 1048576 (initialized to 0)
>>> len(x)
1048576
>>> bitarray('1001 011') # initialize from string (whitespace is ignored)
bitarray('1001011')
>>> lst = [1, 0, False, True, True]
>>> a = bitarray(lst) # initialize from iterable
>>> a
bitarray('10011')
>>> a[2] # indexing a single item will always return an integer
0
>>> a[2:4] # whereas indexing a slice will always return a bitarray
bitarray('01')
>>> a[2:3] # even when the slice length is just one
bitarray('0')
>>> a.count(1)
3
>>> a.remove(0) # removes first occurrence of 0
>>> a
bitarray('1011')Like lists, bitarray objects support slice assignment and deletion:
.. code-block:: python
>>> a = bitarray(50)
>>> a.setall(0) # set all elements in a to 0
>>> a[11:37:3] = 9 * bitarray('1')
>>> a
bitarray('00000000000100100100100100100100100100000000000000')
>>> del a[12::3]
>>> a
bitarray('0000000000010101010101010101000000000')
>>> a[-6:] = bitarray('10011')
>>> a
bitarray('000000000001010101010101010100010011')
>>> a += bitarray('000111')
>>> a[9:]
bitarray('001010101010101010100010011000111')In addition, slices can be assigned to booleans, which is easier (and faster) than assigning to a bitarray in which all values are the same:
.. code-block:: python
>>> a = 20 * bitarray('0')
>>> a[1:15:3] = True
>>> a
bitarray('01001001001001000000')This is easier and faster than:
.. code-block:: python
>>> a = 20 * bitarray('0')
>>> a[1:15:3] = 5 * bitarray('1')
>>> a
bitarray('01001001001001000000')Note that in the latter we have to create a temporary bitarray whose length must be known or calculated. Another example of assigning slices to Booleans, is setting ranges:
.. code-block:: python
>>> a = bitarray(30)
>>> a[:] = 0 # set all elements to 0 - equivalent to a.setall(0)
>>> a[10:25] = 1 # set elements in range(10, 25) to 1
>>> a
bitarray('000000000011111111111111100000')As of bitarray version 2.8, indices may also be lists of arbitrary
indices (like in NumPy), or bitarrays that are treated as masks, see
Bitarray indexing <https://github.com/ilanschnell/bitarray/blob/master/doc/indexing.rst>__.
Bitarray objects support the bitwise operators ~,
&, |, ^,
<<, >> (as well as their in-place
versions &=, |=, ^=,
<<=, >>=). The behavior is very
much what one would expect:
.. code-block:: python
>>> a = bitarray('101110001')
>>> ~a # invert
bitarray('010001110')
>>> b = bitarray('111001011')
>>> a ^ b # bitwise XOR
bitarray('010111010')
>>> a &= b # inplace AND
>>> a
bitarray('101000001')
>>> a <<= 2 # in-place left-shift by 2
>>> a
bitarray('100000100')
>>> b >> 1 # return b right-shifted by 1
bitarray('011100101')The C language does not specify the behavior of negative shifts and of left shifts larger or equal than the width of the promoted left operand. The exact behavior is compiler/machine specific. This Python bitarray library specifies the behavior as follows:
ValueErrorIt is worth noting that (regardless of bit-endianness) the bitarray
left shift (<<) always shifts towards lower indices,
and the right shift (>>) always shifts towards higher
indices.
For many purposes the bit-endianness is not of any relevance to the
end user and can be regarded as an implementation detail of bitarray
objects. However, there are use cases when the bit-endianness becomes
important. These use cases involve explicitly reading and writing the
bitarray buffer using .tobytes(),
.frombytes(), .tofile() or
.fromfile(), importing and exporting buffers. Also, a
number of utility functions in bitarray.util will return
different results depending on bit-endianness, such as
ba2hex() or ba2int. To better understand this
topic, please read
bit-endianness <https://github.com/ilanschnell/bitarray/blob/master/doc/endianness.rst>__.
Bitarray objects support the buffer protocol. They can both export
their own buffer, as well as import another object's buffer. To learn
more about this topic, please read
buffer protocol <https://github.com/ilanschnell/bitarray/blob/master/doc/buffer.rst>.
There is also an example that shows how to memory-map a file to a
bitarray:
mmapped-file.py <https://github.com/ilanschnell/bitarray/blob/master/examples/mmapped-file.py>
The .encode() method takes a dictionary mapping symbols
to bitarrays and an iterable, and extends the bitarray object with the
encoded symbols found while iterating. For example:
.. code-block:: python
>>> d = {'H':bitarray('111'), 'e':bitarray('0'),
... 'l':bitarray('110'), 'o':bitarray('10')}
...
>>> a = bitarray()
>>> a.encode(d, 'Hello')
>>> a
bitarray('111011011010')Note that the string 'Hello' is an iterable, but the
symbols are not limited to characters, in fact any immutable Python
object can be a symbol. Taking the same dictionary, we can apply the
.decode() method which will return an iterable of the
symbols:
.. code-block:: python
>>> list(a.decode(d))
['H', 'e', 'l', 'l', 'o']
>>> ''.join(a.decode(d))
'Hello'Symbols are not limited to being characters. The above dictionary
d can be efficiently constructed using the function
bitarray.util.huffman_code(). I also wrote
Huffman coding in Python using bitarray <http://ilan.schnell-web.net/prog/huffman/>__
for more background information.
When the codes are large, and you have many decode calls, most time
will be spent creating the (same) internal decode tree objects. In this
case, it will be much faster to create a decodetree object,
which can be passed to bitarray's .decode() method, instead
of passing the prefix code dictionary to those methods itself:
.. code-block:: python
>>> from bitarray import bitarray, decodetree
>>> t = decodetree({'a': bitarray('0'), 'b': bitarray('1')})
>>> a = bitarray('0110')
>>> list(a.decode(t))
['a', 'b', 'b', 'a']The sole purpose of the immutable decodetree object is
to be passed to bitarray's .decode() method.
A frozenbitarray object is very similar to the bitarray
object. The difference is that this a frozenbitarray is
immutable, and hashable, and can therefore be used as a dictionary
key:
.. code-block:: python
>>> from bitarray import frozenbitarray
>>> key = frozenbitarray('1100011')
>>> {key: 'some value'}
{frozenbitarray('1100011'): 'some value'}
>>> key[3] = 1
Traceback (most recent call last):
...
TypeError: frozenbitarray is immutablebitarray version: 3.7.2 --
change log <https://github.com/ilanschnell/bitarray/blob/master/doc/changelog.rst>__
In the following, item and value are
usually a single bit - an integer 0 or 1.
Also, sub_bitarray refers to either a bitarray, or an
item.
bitarray(initializer=0, /, endian='big', buffer=None)
-> bitarray Return a new bitarray object whose items are bits
initialized from the optional initializer, and bit-endianness. The
initializer may be one of the following types: a.) int
bitarray, initialized to zeros, of given length b.) bytes
or bytearray to initialize buffer directly c.)
str of 0s and 1s, ignoring whitespace and "_" d.) iterable
of integers 0 or 1.
Optional keyword arguments:
endian: Specifies the bit-endianness of the created
bitarray object. Allowed values are big and
little (the default is big). The
bit-endianness effects the buffer representation of the bitarray.
buffer: Any object which exposes a buffer. When
provided, initializer cannot be present (or has to be
None). The imported buffer may be read-only or writable,
depending on the object type.
New in version 2.3: optional buffer argument
New in version 3.4: allow initializer bytes or
bytearray to set buffer directly
all() -> bool Return True when all bits
in bitarray are 1. a.all() is a faster version of
all(a).
any() -> bool Return True when any bit
in bitarray is 1. a.any() is a faster version of
any(a).
append(item, /) Append item to the end of
the bitarray.
buffer_info() -> BufferInfo Return named tuple with
following fields:
address: memory address of buffernbytes: buffer size (in bytes)endian: bit-endianness as a stringpadbits: number of pad bitsalloc: allocated memory for buffer (in bytes)readonly: memory is read-only (bool)imported: buffer is imported (bool)exports: number of buffer exportsNew in version 3.7: return named tuple
bytereverse(start=0, stop=<end of buffer>, /) For
each byte in byte-range(start, stop) reverse
bits in-place. The start and stop indices are given in terms of bytes
(not bits). Also note that this method only changes the buffer; it does
not change the bit-endianness of the bitarray object. Pad bits are left
unchanged such that two consecutive calls will always leave the bitarray
unchanged.
New in version 2.2.5: optional start and stop arguments
clear() Remove all items from bitarray.
New in version 1.4
copy() -> bitarray Return copy of bitarray (with same
bit-endianness).
count(value=1, start=0, stop=<end>, step=1, /)
-> int Number of occurrences of value bitarray within
[start:stop:step]. Optional arguments start,
stop and step are interpreted in slice
notation, meaning a.count(value, start, stop, step) equals
a[start:stop:step].count(value). The value may
also be a sub-bitarray. In this case non-overlapping occurrences are
counted within [start:stop] (step must be
1).
New in version 1.1.0: optional start and stop arguments
New in version 2.3.7: optional step argument
New in version 2.9: add non-overlapping sub-bitarray count
decode(code, /) -> iterator Given a prefix code (a
dict mapping symbols to bitarrays, or decodetree object),
decode content of bitarray and return an iterator over corresponding
symbols.
See also:
Bitarray 3 transition <https://github.com/ilanschnell/bitarray/blob/master/doc/bitarray3.rst>__
New in version 3.0: returns iterator (equivalent to past
.iterdecode())
encode(code, iterable, /) Given a prefix code (a dict
mapping symbols to bitarrays), iterate over the iterable object with
symbols, and extend bitarray with corresponding bitarray for each
symbol.
extend(iterable, /) Append items from to the end of the
bitarray. If iterable is a (Unicode) string, each
0 and 1 are appended as bits (ignoring
whitespace and underscore).
New in version 3.4: allow bytes object
fill() -> int Add zeros to the end of the bitarray,
such that the length will be a multiple of 8, and return the number of
bits added [0..7].
find(sub_bitarray, start=0, stop=<end>, /, right=False)
-> int Return lowest (or rightmost when right=True)
index where sub_bitarray is found, such that sub_bitarray is contained
within [start:stop]. Return -1 when sub_bitarray is not
found.
New in version 2.1
New in version 2.9: add optional keyword argument
right
frombytes(bytes, /) Extend bitarray with raw bytes from
a bytes-like object. Each added byte will add eight bits to the
bitarray.
New in version 2.5.0: allow bytes-like argument
fromfile(f, n=-1, /) Extend bitarray with up to
n bytes read from file object f (or any other
binary stream what supports a .read() method, e.g.
io.BytesIO). Each read byte will add eight bits to the
bitarray. When n is omitted or negative, reads and extends
all data until EOF. When n is non-negative but exceeds the
available data, EOFError is raised. However, the available
data is still read and extended.
index(sub_bitarray, start=0, stop=<end>, /, right=False)
-> int Return lowest (or rightmost when right=True)
index where sub_bitarray is found, such that sub_bitarray is contained
within [start:stop]. Raises ValueError when
sub_bitarray is not present.
New in version 2.9: add optional keyword argument
right
insert(index, value, /) Insert value into
bitarray before index.
invert(index=<all bits>, /) Invert all bits in
bitarray (in-place). When the optional index is given, only
invert the single bit at index.
New in version 1.5.3: optional index argument
pack(bytes, /) Extend bitarray from a bytes-like object,
where each byte corresponds to a single bit. The byte
b'\x00' maps to bit 0 and all other bytes map to bit 1.
This method, as well as the .unpack() method, are meant
for efficient transfer of data between bitarray objects to other Python
objects (for example NumPy's ndarray object) which have a different
memory view.
New in version 2.5.0: allow bytes-like argument
pop(index=-1, /) -> item Remove and return item at
index (default last). Raises IndexError if
index is out of range.
remove(value, /) Remove the first occurrence of
value. Raises ValueError if value is not
present.
reverse() Reverse all bits in bitarray (in-place).
search(sub_bitarray, start=0, stop=<end>, /, right=False)
-> iterator Return iterator over indices where sub_bitarray is found,
such that sub_bitarray is contained within [start:stop].
The indices are iterated in ascending order (from lowest to highest),
unless right=True, which will iterate in descending order
(starting with rightmost match).
See also:
Bitarray 3 transition <https://github.com/ilanschnell/bitarray/blob/master/doc/bitarray3.rst>__
New in version 2.9: optional start and stop arguments - add optional
keyword argument right
New in version 3.0: returns iterator (equivalent to past
.itersearch())
setall(value, /) Set all elements in bitarray to
value. Note that a.setall(value) is equivalent
to a[:] = value.
sort(reverse=False) Sort all bits in bitarray
(in-place).
to01(group=0, sep=' ') -> str Return bitarray as
(Unicode) string of 0s and 1s. The bits are
grouped into group bits (default is no grouping). When
grouped, the string sep is inserted between groups of
group characters, default is a space.
New in version 3.3: optional group and sep
arguments
tobytes() -> bytes Return the bitarray buffer (pad
bits are set to zero).
tofile(f, /) Write bitarray buffer to file object
f.
tolist() -> list Return bitarray as list of integers.
a.tolist() equals list(a).
Note that the list object being created will require 32 or 64 times more memory (depending on the machine architecture) than the bitarray object, which may cause a memory error if the bitarray is very large.
unpack(zero=b'\x00', one=b'\x01') -> bytes Return
bytes that contain one byte for each bit in the bitarray, using
specified mapping.
Data descriptors were added in version 2.6.
endian -> str bit-endianness as Unicode string
New in version 3.4: replaces former .endian() method
nbytes -> int buffer size in bytes
padbits -> int number of pad bits
readonly -> bool bool indicating whether buffer is
read-only
frozenbitarray(initializer=0, /, endian='big', buffer=None)
-> frozenbitarray Return a frozenbitarray object.
Initialized the same way a bitarray object is initialized.
A frozenbitarray is immutable and hashable, and may
therefore be used as a dictionary key.
New in version 1.1
decodetree(code, /) -> decodetree Given a prefix code
(a dict mapping symbols to bitarrays), create a binary tree object to be
passed to .decode().
New in version 1.6
bitarray module:bits2bytes(n, /) -> int Return the number of bytes
necessary to store n bits.
get_default_endian() -> str Return the default
bit-endianness for new bitarray objects being created. Unless
_set_default_endian('little') was called, the default
bit-endianness is big.
New in version 1.3
test(verbosity=1) -> TextTestResult Run self-test,
and return unittest.runner.TextTestResult object.
bitarray.util module:This sub-module was added in version 1.2.
any_and(a, b, /) -> bool Efficient implementation of
any(a & b).
New in version 2.7
ba2base(n, bitarray, /, group=0, sep=' ') -> str
Return a string containing the base n ASCII representation
of the bitarray. Allowed values for n are 2, 4, 8, 16, 32
and 64. The bitarray has to be multiple of length 1, 2, 3, 4, 5 or 6
respectively. For n=32 the RFC 4648 Base32 alphabet is
used, and for n=64 the standard base 64 alphabet is used.
When grouped, the string sep is inserted between groups of
group characters, default is a space.
See also:
Bitarray representations <https://github.com/ilanschnell/bitarray/blob/master/doc/represent.rst>__
New in version 1.9
New in version 3.3: optional group and sep
arguments
ba2hex(bitarray, /, group=0, sep=' ') -> hexstr
Return a string containing the hexadecimal representation of the
bitarray (which has to be multiple of 4 in length). When grouped, the
string sep is inserted between groups of group
characters, default is a space.
New in version 3.3: optional group and sep
arguments
ba2int(bitarray, /, signed=False) -> int Convert the
given bitarray to an integer. The bit-endianness of the bitarray is
respected. signed indicates whether two's complement is
used to represent the integer.
base2ba(n, asciistr, /, endian=None) -> bitarray
Bitarray of base n ASCII representation. Allowed values for
n are 2, 4, 8, 16, 32 and 64. For n=32 the RFC
4648 Base32 alphabet is used, and for n=64 the standard
base 64 alphabet is used. Whitespace is ignored.
See also:
Bitarray representations <https://github.com/ilanschnell/bitarray/blob/master/doc/represent.rst>__
New in version 1.9
New in version 3.3: ignore whitespace
byteswap(a, n=<buffer size>, /) Reverse every
n consecutive bytes of a in-place. By default,
all bytes are reversed. Note that n is not limited to 2, 4
or 8, but can be any positive integer. Also, a may be any
object that exposes a writable buffer. Nothing about this function is
specific to bitarray objects.
We should mention that Python's array.array object has a
method .byteswap() with similar functionality. However,
unlike bitarray's util.byteswap() function, this method is
limited to swapping 2, 4, or 8 consecutive bytes.
New in version 3.4
canonical_decode(bitarray, count, symbol, /) ->
iterator Decode bitarray using canonical Huffman decoding tables where
count is a sequence containing the number of symbols of
each length and symbol is a sequence of symbols in
canonical order.
See also:
Canonical Huffman Coding <https://github.com/ilanschnell/bitarray/blob/master/doc/canonical.rst>__
New in version 2.5
canonical_huffman(dict, /) -> tuple Given a frequency
map, a dictionary mapping symbols to their frequency, calculate the
canonical Huffman code. Returns a tuple containing:
Note: the two lists may be used as input for
canonical_decode().
See also:
Canonical Huffman Coding <https://github.com/ilanschnell/bitarray/blob/master/doc/canonical.rst>__
New in version 2.5
correspond_all(a, b, /) -> tuple Return tuple with
counts of: ~a & ~b, ~a & b, a & ~b, a & b
New in version 3.4
count_and(a, b, /) -> int Return
(a & b).count() in a memory efficient manner, as no
intermediate bitarray object gets created.
count_n(a, n, value=1, /) -> int Return lowest index
i for which a[:i].count(value) == n. Raises
ValueError when n exceeds total count
(a.count(value)).
New in version 2.3.6: optional value argument
count_or(a, b, /) -> int Return
(a | b).count() in a memory efficient manner, as no
intermediate bitarray object gets created.
count_xor(a, b, /) -> int Return
(a ^ b).count() in a memory efficient manner, as no
intermediate bitarray object gets created.
This is also known as the Hamming distance.
deserialize(bytes, /) -> bitarray Return a bitarray
given a bytes-like representation such as returned by
serialize().
See also:
Bitarray representations <https://github.com/ilanschnell/bitarray/blob/master/doc/represent.rst>__
New in version 1.8
New in version 2.5.0: allow bytes-like argument
gen_primes(n, /, endian=None, odd=False) -> bitarray
Generate a bitarray of length n in which active indices are
prime numbers. By default (odd=False), active indices
correspond to prime numbers directly. When odd=True, only
odd prime numbers are represented in the resulting bitarray
a, and a[i] corresponds to 2*i+1
being prime or not.
Apart from working with prime numbers, this function is useful for testing, as it provides a simple way to create a well-defined bitarray of any length.
New in version 3.7
hex2ba(hexstr, /, endian=None) -> bitarray Bitarray
of hexadecimal representation. hexstr may contain any number (including
odd numbers) of hex digits (upper or lower case). Whitespace is
ignored.
New in version 3.3: ignore whitespace
huffman_code(dict, /, endian=None) -> dict Given a
frequency map, a dictionary mapping symbols to their frequency,
calculate the Huffman code, i.e. a dict mapping those symbols to
bitarrays (with given bit-endianness). Note that the symbols are not
limited to being strings. Symbols may be any hashable object.
int2ba(int, /, length=None, endian=None, signed=False)
-> bitarray Convert the given integer to a bitarray (with given
bit-endianness, and no leading (big-endian) / trailing (little-endian)
zeros), unless the length of the bitarray is provided. An
OverflowError is raised if the integer is not representable
with the given number of bits. signed determines whether
two's complement is used to represent the integer, and requires
length to be provided.
intervals(bitarray, /) -> iterator Compute all
uninterrupted intervals of 1s and 0s, and return an iterator over tuples
(value, start, stop). The intervals are guaranteed to be in
order, and their size is always non-zero
(stop - start > 0).
New in version 2.7
ones(n, /, endian=None) -> bitarray Create a bitarray
of length n, with all values 1, and optional
bit-endianness (little or big).
New in version 2.9
parity(a, /) -> int Return parity of bitarray
a. parity(a) is equivalent to
a.count() % 2 but more efficient.
New in version 1.9
pprint(bitarray, /, stream=None, group=8, indent=4, width=80)
Pretty-print bitarray object to stream, defaults is
sys.stdout. By default, bits are grouped in bytes (8 bits),
and 64 bits per line. Non-bitarray objects are printed using
pprint.pprint().
New in version 1.8
random_k(n, /, k, endian=None) -> bitarray Return
(pseudo-) random bitarray of length n with k
elements set to one. Mathematically equivalent to setting (in a bitarray
of length n) all bits at indices
random.sample(range(n), k) to one. The random bitarrays are
reproducible when giving Python's random.seed() a specific
seed value.
New in version 3.6
random_p(n, /, p=0.5, endian=None) -> bitarray Return
(pseudo-) random bitarray of length n, where each bit has
probability p of being one (independent of any other bits).
Mathematically equivalent to
bitarray((random() < p for _ in range(n)), endian), but
much faster for large n. The random bitarrays are
reproducible when giving Python's random.seed() with a
specific seed value.
This function requires Python 3.12 or higher, as it depends on the
standard library function random.binomialvariate(). Raises
NotImplementedError when Python version is too low.
See also:
Random Bitarrays <https://github.com/ilanschnell/bitarray/blob/master/doc/random_p.rst>__
New in version 3.5
sc_decode(stream, /) -> bitarray Decompress binary
stream (an integer iterator, or bytes-like object) of a sparse
compressed (sc) bitarray, and return the decoded bitarray.
This function consumes only one bitarray and leaves the remaining stream
untouched. Use sc_encode() for compressing (encoding).
See also:
Compression of sparse bitarrays <https://github.com/ilanschnell/bitarray/blob/master/doc/sparse_compression.rst>__
New in version 2.7
sc_encode(bitarray, /) -> bytes Compress a sparse
bitarray and return its binary representation. This representation is
useful for efficiently storing sparse bitarrays. Use
sc_decode() for decompressing (decoding).
See also:
Compression of sparse bitarrays <https://github.com/ilanschnell/bitarray/blob/master/doc/sparse_compression.rst>__
New in version 2.7
serialize(bitarray, /) -> bytes Return a serialized
representation of the bitarray, which may be passed to
deserialize(). It efficiently represents the bitarray
object (including its bit-endianness) and is guaranteed not to change in
future releases.
See also:
Bitarray representations <https://github.com/ilanschnell/bitarray/blob/master/doc/represent.rst>__
New in version 1.8
strip(bitarray, /, mode='right') -> bitarray Return a
new bitarray with zeros stripped from left, right or both ends. Allowed
values for mode are the strings: left, right,
both
subset(a, b, /) -> bool Return True if
bitarray a is a subset of bitarray b.
subset(a, b) is equivalent to a | b == b (and
equally a & b == a) but more efficient as no
intermediate bitarray object is created and the buffer iteration is
stopped as soon as one mismatch is found.
sum_indices(a, /, mode=1) -> int Return sum of
indices of all active bits in bitarray a. Equivalent to
sum(i for i, v in enumerate(a) if v). mode=2
sums square of indices.
New in version 3.6
New in version 3.7: add optional mode argument
urandom(n, /, endian=None) -> bitarray Return random
bitarray of length n (uses os.urandom()).
New in version 1.7
vl_decode(stream, /, endian=None) -> bitarray Decode
binary stream (an integer iterator, or bytes-like object), and return
the decoded bitarray. This function consumes only one bitarray and
leaves the remaining stream untouched. Use vl_encode() for
encoding.
See also:
Variable length bitarray format <https://github.com/ilanschnell/bitarray/blob/master/doc/variable_length.rst>__
New in version 2.2
vl_encode(bitarray, /) -> bytes Return variable
length binary representation of bitarray. This representation is useful
for efficiently storing small bitarray in a binary stream. Use
vl_decode() for decoding.
See also:
Variable length bitarray format <https://github.com/ilanschnell/bitarray/blob/master/doc/variable_length.rst>__
New in version 2.2
xor_indices(a, /) -> int Return xor reduced indices
of all active bits in bitarray a. This is essentially
equivalent to
reduce(operator.xor, (i for i, v in enumerate(a) if v)).
New in version 3.2
zeros(n, /, endian=None) -> bitarray Create a
bitarray of length n, with all values 0, and
optional bit-endianness (little or big).