---
title: math.nextafter() function
description: math.nextafter() returns the next representable float value after x towards y.
url: https://docs.influxdata.com/flux/v0/stdlib/math/nextafter/
estimated_tokens: 1238
product: Flux
version: v0
---

# math.nextafter() function

-   Flux 0.22.0+
-   View InfluxDB support

`math.nextafter()` returns the next representable float value after `x` towards `y`.

##### Function type signature

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

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

## Parameters

### x

(Required) x-value to use in the operation.

### y

(Required) y-value to use in the operation.

## Examples

-   [Return the next possible float value](#return-the-next-possible-float-value)
-   [Use math.nextafter in map](#use-mathnextafter-in-map)

### Return the next possible float value

```js
import "math"

math.nextafter(x: 1.23, y: 4.56)// 1.2300000000000002

```

### Use math.nextafter in map

```js
import "math"

data
    |> map(fn: (r) => ({_time: r._time, _value: math.nextafter(x: r.t1, y: r.t2)}))
```

[](#view-example-input-and-output)

View example input and output

#### Input data

| _time | t1 | t2 |
| --- | --- | --- |
| 2021-01-01T00:00:00Z | -2.18 | 19.85 |
| 2021-01-01T00:00:10Z | 10.92 | 4.97 |
| 2021-01-01T00:00:20Z | 7.35 | -3.75 |
| 2021-01-01T00:00:30Z | 17.53 | 19.77 |
| 2021-01-01T00:00:40Z | 15.23 | 13.86 |
| 2021-01-01T00:00:50Z | 4.43 | 1.86 |

#### Output data

| _time | _value |
| --- | --- |
| 2021-01-01T00:00:00Z | -2.1799999999999997 |
| 2021-01-01T00:00:10Z | 10.919999999999998 |
| 2021-01-01T00:00:20Z | 7.349999999999999 |
| 2021-01-01T00:00:30Z | 17.530000000000005 |
| 2021-01-01T00:00:40Z | 15.229999999999999 |
| 2021-01-01T00:00:50Z | 4.429999999999999 |