mathjs/docs/reference/functions/not.md

Math.js is an extensive math library for JavaScript and Node.js. It features a flexible expression parser with support for symbolic computation, comes with a large set of built-in functions and constants, and offers an integrated solution to work with dif

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# Function not

Logical `not`. Flips boolean value of a given parameter.
For matrices, the function is evaluated element wise.


## Syntax

```js
math.not(x)
```

### Parameters

Parameter | Type | Description
--------- | ---- | -----------
`x` | number &#124; BigNumber &#124; Complex &#124; Unit &#124; Array &#124; Matrix | First value to check

### Returns

Type | Description
---- | -----------
boolean &#124; Array &#124; Matrix |  Returns true when input is a zero or empty value.


## Examples

```js
math.not(2)      // returns false
math.not(0)      // returns true
math.not(true)   // returns false

a = [2, -7, 0]
math.not(a)      // returns [false, false, true]
```


## See also

[and](and.md),
[or](or.md),
[xor](xor.md)