72 lines
1.7 KiB
Markdown
72 lines
1.7 KiB
Markdown
---
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id: t127
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tags: [binary]
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created: Saturday, April 20, 2024
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---
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# Bitwise operators
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In addition to mathematical, logical and comparison operators, there are
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_bitwise operators_. These operators execute conditions based on the actual bits
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of a value rather than the values that the bits are encoded to represent.
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Bitwise operators are typically represented with single characters of existing
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operators, e.g. `&` instead of `&&`:
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| Bitwise operation | Operator |
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| ----------------- | ------------- |
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| AND | `&` |
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| OR | (single pipe) |
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| NOT | `~` |
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An example of using the `&` operator:
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```py
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x = 5
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y = 3
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a = x & y
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b = x | y
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```
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The value of `a` will be 1. The reason is we are looking at the bit values of
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`x` and `y` and then applying Boolean AND to each bit:
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```
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x = 5 = 0101
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y = 3 = 0011
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a = 1 = 0001
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```
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Working from right to left for each column:
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- true and true = true
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- false and true = false
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- true and false = false
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- false and false = false
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This leaves us with 0001 which is equal to 1 in binary and denary.
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For the case of bitwise OR we get 7 as the result of `x | y`:
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```
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x = 5 = 0101
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y = 3 = 0011
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b = 7 = 0111
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```
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- true or true = true
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- false or true = true
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- true or false = true
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- false or false = true
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This leaves us with 0111 which is equal to 7 in denary.
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## Why use them?
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Bitwise operations are more of a hallmark of lower-level programming. As bit
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operations are the fastest and lowest level of computation, being able to
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directly access and operate on bits within a programming language can be
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beneficial when efficiency and speed of execution is a factor or when memory is
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constrained.
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## Related notes
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