BitVector 2.2

A pure-Python memory-efficient packed representation for bit arrays

This class presents a pure-Python memory-efficient packed representation for bit arrays.

Version 2.2 includes a couple of bug fixes and a new method runs() that returns a list of strings that are consecutive runs of 1’s and 0’s in the bit vector. This version also allows for chained invocations of circular bit shift operations.

Version 2.1 includes enhanced support for folks who use this class for computer security and cryptography work. You can now call on the methods of the BitVector class to do Galois Field GF(2^n) arithmetic on bit arrays. This should save the users of this class the bother of having to write their own routines for finding multiplicative inverses in GF(2^n) finite fields.

Version 2.0 provides much additional functionality that was requested by folks in the data mining community.

The class supports the following operators/methods:

• __getitem__

• __setitem__

• __len__

• __iter__

• __contains__

• __getslice__

• __str__

• __int__

• __add__

• __eq__, __ne__, __lt__, __le__, __gt__, __ge__

• __or__

• __and__

• __xor__

• __invert__

• __lshift__

• __rshift__

• __add__

• count_bits

• count_bit_sparse (faster for sparse bit vectors)

• deep_copy

• divide_into_two

• gcd

• gf_divide (for divisions in GF(2^n))

• gf_MI (for multiplicative inverse in GF(2^n))

• gf_multiply (for multiplications in GF(2))

• gf_multiply_modular (for multiplications in GF(2^n))

• hamming_distance

• intValue (for returning the integer value)

• isPowerOf2

• isPowerOf2_sparse (faster for sparse bit vectors)

• jaccard_distance

• jaccard_similarity

• length

• multiplicative_inverse

• next_set_bit

• pad_from_left

• pad_from_right

• permute

• rank_of_bit_set_at_index

• read_bits_from_file

• read_bits_from_fileobject

• reset

• reverse

• runs

• shift_left for non-circular left shift

• shift_right for non-circular right shift

• slice assignment

• setValue

• unpermute

• write_to_file

• write_bits_to_fileobject