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Simple construction, analysis and modification of binary data.

Project description

bitstring is a pure Python module designed to help make the creation and analysis of binary data as simple and natural as possible.

Bitstrings can be constructed from integers (big and little endian), hex, octal, binary, strings or files. They can be sliced, joined, reversed, inserted into, overwritten, etc. with simple functions or slice notation. They can also be read from, searched and replaced, and navigated in, similar to a file or stream.

bitstring is open source software, and has been released under the MIT licence.

This version supports Python 2.6 and later (including Python 3). For Python 2.4 and 2.5 you should instead download version 1.0.


The manual for the bitstring module is available here <>. It contains a walk-through of all the features and a complete reference section.

It is also available as a PDF as part of the source download.


If you have downloaded and unzipped the package then you need to run the script with the ‘install’ argument:

python install

You may need to run this with root privileges on Unix-like systems.

If you haven’t yet downloaded the package then you can just try:

easy_install bitstring


pip install bitstring

If you’re using Windows then there is an installer available from the downloads tab on the project’s homepage.

Simple Examples


>>> a = BitArray(bin='00101')
>>> b = ConstBitArray(a_file_object)
>>> c = BitArray('0xff, 0b101, 0o65, uint:6=22')
>>> d = pack('intle:16, hex=a, 0b1', 100, a='0x34f')
>>> e = pack('<16h', *range(16))

Different interpretations, slicing and concatenation:

>>> a = BitArray('0x1af')
>>> a.hex, a.bin, a.uint
('0x1af', '0b000110101111', 431)
>>> a[10:3:-1].bin
>>> 3*a + '0b100'

Reading data sequentially:

>>> b = BitStream('0x160120f')
>>> b.pos = 0
>>> b.readlist('uint:12, bin:3')
[288, '0b111']

Searching, inserting and deleting:

>>> c = BitArray('0b00010010010010001111')   # c.hex == '0x1248f'
>>> c.find('0x48')
>>> c.replace('0b001', '0xabc')
>>> c.insert('0b0000')
>>> del c[12:16]

Unit Tests

The 400+ unit tests should all pass for Python 2.6 and later.

The bitstring module has been released as open source under the MIT License. Copyright (c) 2011 Scott Griffiths

For more information see the project’s homepage on Google Code: <>

Project details

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