# Bit Array

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A Bit Array is an array whose elements are binary digits.

**See:**Bit Matrix, Bloom Filter, Associative Array.

## References

### 2013

- http://en.wikipedia.org/wiki/Bit_array
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**bit array**(also known as bitmap,**bitset**, bit string, or**bit vector**) is an array data structure that compactly stores bits. It can be used to implement a simple set data structure. A bit array is effective at exploiting bit-level parallelism in hardware to perform operations quickly. A typical bit array stores*kw*bits, where*w*is the number of bits in the unit of storage, such as a byte or word, and*k*is some nonnegative integer. If*w*does not divide the number of bits to be stored, some space is wasted due to internal fragmentation.

- A

- http://en.wikipedia.org/wiki/Bit_array#Definition
- A bit array is a mapping from some domain (almost always a range of integers) to values in the set {0, 1}. The values can be interpreted as dark/light, absent/present, locked/unlocked, valid/invalid, et cetera. The point is that there are only two possible values, so they can be stored in one bit. The array can be viewed as a subset of the domain (e.g. {0, 1, 2, ...,
*n*−1}), where a 1 bit indicates a number in the set and a 0 bit a number not in the set. This set data structure uses about*n*/*w*words of space, where*w*is the number of bits in each machine word. Whether the least significant bit or the most significant bit indicates the smallest-index number is largely irrelevant, but the former tends to be preferred.

- A bit array is a mapping from some domain (almost always a range of integers) to values in the set {0, 1}. The values can be interpreted as dark/light, absent/present, locked/unlocked, valid/invalid, et cetera. The point is that there are only two possible values, so they can be stored in one bit. The array can be viewed as a subset of the domain (e.g. {0, 1, 2, ...,