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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.

This version supports Python 2.6 and 3.x. For Python 2.4 and 2.5 you should instead download version 1.0.0.


The manual for the bitstring module is available as a PDF. It contains a walk-through of all the features and a complete reference section. It can be dowloaded or viewed on the project’s homepage.

Simple Examples


>>> a = BitString(bin='00101')
>>> b = BitString(a_file_object)
>>> c = BitString('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 = BitString('0x1af')
>>> a.hex, a.bin, a.uint
('0x1af', '0b000110101111', 431)
>>> a[10:3:-1].bin
>>> 3*a + '0b100'

Reading data sequentially:

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

Searching, inserting and deleting:

>>> c = BitString('0b00010010010010001111')   # c.hex == '0x1248f'
>>> c.find('0x48')
>>> c.replace('0b001', '0xabc')
>>> c.insert('0b0000')
>>> c.delete(4, 12)


First try:

easy_install bitstring

If you don’t have easy_install then download the zip file and run the script with the ‘install’ argument:

python install

This should put in your site-packages directory. You may need to run this with root privileges on Unix-like systems.

Alternatively just copy the file to where you want it!

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

Unit Tests

To run the unit tests:


The unit tests for version 1.1.0 should all pass for Python 2.6, 3.0 and 3.1.

The bitstring module has been released as open source under the MIT License. Copyright (c) 2009 Scott Griffiths

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

Project details

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