> ## 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.

# array_split

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

The `array_split` function in APL splits an array into smaller subarrays based on specified split indices and packs the generated subarrays into a dynamic array. This function is useful when you want to partition data for analysis, batch processing, or distributing workloads across smaller units.

You can use `array_split` to:

* Divide large datasets into manageable chunks for processing.
* Create segments for detailed analysis or visualization.
* Handle nested data structures for targeted processing.

## 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, array manipulation is achieved through functions like `mvzip` and `mvfilter`, but there is no direct equivalent to `array_split`. APL provides a more explicit approach for splitting arrays.

    <CodeGroup>
      ```sql Splunk example theme={null}
      | eval split_array = mvzip(array_field, "2")
      ```

      ```kusto APL equivalent theme={null}
      ['otel-demo-traces']
      | extend split_array = array_split(events, 2)
      ```
    </CodeGroup>
  </Accordion>

  <Accordion title="ANSI SQL users">
    ANSI SQL doesn’t have built-in functions for directly splitting arrays. APL provides this capability natively, making it easier to handle array operations within queries.

    <CodeGroup>
      ```sql SQL example theme={null}
      -- SQL typically requires custom functions or JSON manipulation.
      SELECT * FROM dataset WHERE JSON_ARRAY_LENGTH(array_field) > 0;
      ```

      ```kusto APL equivalent theme={null}
      ['otel-demo-traces']
      | extend split_array = array_split(events, 2)
      ```
    </CodeGroup>
  </Accordion>
</AccordionGroup>

## Usage

### Syntax

```kusto theme={null}
array_split(array, index)
```

### Parameters

| Parameter | Description                                                                                                                | Type               |
| --------- | -------------------------------------------------------------------------------------------------------------------------- | ------------------ |
| `array`   | The array to split.                                                                                                        | Dynamic            |
| `index`   | An integer or dynamic array of integers. These zero-based split indices indicate the location at which to split the array. | Integer or Dynamic |

### Returns

Returns a dynamic array containing N+1 arrays where N is the number of input indices. The original array is split at the input indices.

## Use case examples

### Single split index

Split large event arrays into manageable chunks for analysis.

```kusto theme={null}
['otel-demo-traces']
| where array_length(events) == 3
| extend split_events = array_split(events, 2)
```

[Run in Playground](https://play.axiom.co/axiom-play-qf1k/query?initForm=%7B%22apl%22%3A%22%5B'otel-demo-traces'%5D%20%7C%20where%20array_length\(events\)%20%3D%3D%203%20%7C%20extend%20span_chunks%20%3D%20array_split\(events%2C%202\)%22%7D)

**Output**

```json events theme={null}
[
  {
    "timestamp": 1734033733465219300,
    "name": "Enqueued"
  },
  {
    "name": "Sent",
    "timestamp": 1734033733465228500
  },
  {
    "timestamp": 1734033733465455900,
    "name": "ResponseReceived"
  }
]
```

```json split_events theme={null}
[
  [
    {
      "timestamp": 1734033733465219300,
      "name": "Enqueued"
    },
    {
      "name": "Sent",
      "timestamp": 1734033733465228500
    }
  ],
  [
    {
      "timestamp": 1734033733465455900,
      "name": "ResponseReceived"
    }
  ]
]
```

This query splits the `events` array at index `2` into two subarrays for further processing.

### Multiple split indeces

Divide traces into fixed-size segments for better debugging.

**Query**

```kusto theme={null}
['otel-demo-traces']
| where array_length(events) == 3
| extend split_events = array_split(events, dynamic([1,2]))
```

[Run in Playground](https://play.axiom.co/axiom-play-qf1k/query?initForm=%7B%22apl%22%3A%22%5B'otel-demo-traces'%5D%20%7C%20where%20array_length\(events\)%20%3D%3D%203%20%7C%20extend%20span_chunks%20%3D%20array_split\(events%2C%20dynamic\(%5B1%2C2%5D\)\)%22%7D)

**Output**

```json events theme={null}
[
  {
    "attributes": null,
    "name": "Enqueued",
    "timestamp": 1734034755085206000
  },
  {
    "name": "Sent",
    "timestamp": 1734034755085215500,
    "attributes": null
  },
  {
    "attributes": null,
    "name": "ResponseReceived",
    "timestamp": 1734034755085424000
  }
]
```

```json split_events theme={null}
[
  [
    {
      "timestamp": 1734034755085206000,
      "attributes": null,
      "name": "Enqueued"
    }
  ],
  [
    {
      "timestamp": 1734034755085215500,
      "attributes": null,
      "name": "Sent"
    }
  ],
  [
    {
      "attributes": null,
      "name": "ResponseReceived",
      "timestamp": 1734034755085424000
    }
  ]
]
```

This query splits the `events` array into three subarrays based on the indices `[1,2]`.

## List of related functions

* [array\_index\_of](/apl/scalar-functions/array-functions/array-index-of): Finds the index of an element in an array.
* [array\_rotate\_right](/apl/scalar-functions/array-functions/array-rotate-right): Rotates array elements to the right by a specified number of positions.
* [array\_shift\_left](/apl/scalar-functions/array-functions/array-shift-left): Shifts array elements one position to the left, moving the first element to the last position.