---
title: math.log() function
description: >
  `math.log()` returns the natural logarithm of `x`.
menu:
  flux_v0_ref:
    name: math.log
    parent: math
    identifier: math/log
weight: 101
---

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`math.log()` returns the natural logarithm of `x`.



##### Function type signature

```js
(x: float) => float
```

{{% caption %}}
For more information, see [Function type signatures](/flux/v0/function-type-signatures/).
{{% /caption %}}

## Parameters

### x
({{< req >}})
Value to operate on.




## Examples

- [Return the natural logarithm of a value](#return-the-natural-logarithm-of-a-value)
- [Use math.log in map](#use-mathlog-in-map)

### Return the natural logarithm of a value

```js
import "math"

math.log(x: 3.14)// 1.144222799920162


```


### Use math.log in map

```js
import "sampledata"
import "math"

sampledata.float()
    |> map(fn: (r) => ({r with _value: math.log(x: r._value)}))

```