mathjs/docs/reference/functions/not.md

Math.js is an extensive math library for JavaScript and Node.js. It features a flexible expression parser and offers an integrated solution to work with numbers, big numbers, complex numbers, units, and matrices.

# 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 | BigNumber | Boolean | Complex | Unit | Array | Matrix | null | First value to check

### Returns

Type | Description
---- | -----------
Boolean | Array | 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)


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