> ## Documentation Index
> Fetch the complete documentation index at: https://axiom.co/docs/llms.txt
> Use this file to discover all available pages before exploring further.

<AgentInstructions>

## Submitting Feedback

If you encounter incorrect, outdated, or confusing documentation on this page, submit feedback:

POST https://axiom.co/docs/feedback

```json
{
  "path": "/apl/scalar-functions/mathematical-functions/abs",
  "feedback": "Description of the issue"
}
```

Only submit feedback when you have something specific and actionable to report.

</AgentInstructions>

# abs

> This page explains how to use the abs function in APL.

Use the `abs` function in APL to compute the absolute value of a numeric expression or timespan. The function removes the sign from the input, so it always returns a non-negative result.

`abs` is useful whenever you care about the magnitude of a deviation rather than its direction. For example, you can use it to measure how far a request latency strays from a baseline, or how large a fluctuation in a metric is regardless of whether it's above or below the expected value.

## For users of other query languages

If you come from other query languages, this section explains how to adjust your existing queries to achieve the same results in APL.

<AccordionGroup>
  <Accordion title="Splunk SPL users">
    In Splunk SPL, the `abs()` function works identically: it takes a single numeric argument and returns its absolute value.

    <CodeGroup>
      ```sql Splunk example theme={null}
      | eval deviation = abs(req_duration_ms - 100)
      ```

      ```kusto APL equivalent theme={null}
      ['sample-http-logs']
      | extend deviation = abs(req_duration_ms - 100)
      ```
    </CodeGroup>
  </Accordion>

  <Accordion title="ANSI SQL users">
    In ANSI SQL, `ABS()` is a standard built-in function with the same semantics as in APL.

    <CodeGroup>
      ```sql SQL example theme={null}
      SELECT ABS(req_duration_ms - 100) AS deviation FROM logs
      ```

      ```kusto APL equivalent theme={null}
      ['sample-http-logs']
      | extend deviation = abs(req_duration_ms - 100)
      ```
    </CodeGroup>
  </Accordion>
</AccordionGroup>

## Usage

### Syntax

```kusto theme={null}
abs(x)
```

### Parameters

| Name | Type                   | Required | Description                                 |
| ---- | ---------------------- | -------- | ------------------------------------------- |
| `x`  | int, real, or timespan | Yes      | The value to compute the absolute value of. |

### Returns

The absolute value of `x`. The return type matches the input type.

## Example

Use `abs` to find how far each request's duration deviates from a 200 ms baseline.

**Query**

```kusto theme={null}
['sample-http-logs']
| extend deviation = abs(req_duration_ms - 200)
| project _time, id, req_duration_ms, deviation
| order by deviation desc
```

[Run in Playground](https://play.axiom.co/axiom-play-qf1k/query?initForm=%7B%22apl%22%3A%20%22%5B%27sample-http-logs%27%5D%20%7C%20extend%20deviation%20%3D%20abs%28req_duration_ms%20-%20200%29%20%7C%20project%20_time%2C%20id%2C%20req_duration_ms%2C%20deviation%20%7C%20order%20by%20deviation%20desc%22%7D)

**Output**

| \_time              | id     | req\_duration\_ms | deviation |
| ------------------- | ------ | ----------------- | --------- |
| 2024-11-14 10:00:00 | user-1 | 450.0             | 250.0     |
| 2024-11-14 10:01:00 | user-2 | 80.0              | 120.0     |
| 2024-11-14 10:02:00 | user-3 | 205.0             | 5.0       |

## List of related functions

* [round](/apl/scalar-functions/mathematical-functions/round): Rounds a value to a specified number of decimal places. Use it when you want to reduce precision rather than compute magnitude.
* [sign](/apl/scalar-functions/mathematical-functions/sign): Returns the sign of a numeric value (+1, 0, or -1). Use it when you want to know direction rather than magnitude.
* [sqrt](/apl/scalar-functions/mathematical-functions/sqrt): Returns the square root. Use it to compute the root-mean-square of deviations for standard deviation calculations.
* [pow](/apl/scalar-functions/mathematical-functions/pow): Raises a value to a power. Use it to square deviations when computing variance.
* [log](/apl/scalar-functions/mathematical-functions/log): Returns the natural logarithm. Use it when you need to work on a logarithmic scale rather than with raw magnitudes.