# isarray



The `isarray` function in APL checks whether a specified value is an array. Use this function to validate input data, handle dynamic schemas, or filter for records where a field is explicitly an array. It’s particularly useful when working with data that contains fields with mixed data types or optional nested arrays.

## Usage [#usage]

### Syntax [#syntax]

```kusto
isarray(value)
```

### Parameters [#parameters]

| Parameter | Description                          |
| --------- | ------------------------------------ |
| `value`   | The value to check if it’s an array. |

### Returns [#returns]

A boolean value:

* `true` if the specified value is an array.
* `false` otherwise.

## Use case example [#use-case-example]

Filter for records where the `events` field contains an array.

**Query**

```kusto
['otel-demo-traces']
| take 50
| summarize events_array = make_list(events)
| extend is_array = isarray(events_array)
```

[Run in Playground](https://play.axiom.co/axiom-play-qf1k/query?initForm=%7B%22apl%22%3A%22%5B'otel-demo-traces'%5D%20%7C%20take%2050%20%7C%20summarize%20events_array%20%3D%20make_list\(events\)%20%7C%20extend%20is_array%20%3D%20isarray\(events_array\)%22%7D)

**Output**

| is\_array |
| --------- |
| true      |

## List of related functions [#list-of-related-functions]

* [array\_length](/apl/scalar-functions/array-functions/array-length): Returns the number of elements in an array.
* [array\_index\_of](/apl/scalar-functions/array-functions/array-index-of): Finds the index of an element in an array.
* [array\_slice](/apl/scalar-functions/array-functions/array-slice): Extracts a subset of elements from an array.

## Other query languages [#other-query-languages]

<LanguageComparisons>
  <Accordion title="Splunk SPL users">
    In Splunk SPL, similar functionality is achieved by analyzing the data structure manually, as SPL doesn’t have a direct equivalent to `isarray`. APL simplifies this task by providing the `isarray` function to directly evaluate whether a value is an array.

    <CodeGroup>
      ```sql Splunk example
      | eval is_array=if(isnotnull(mvcount(field)), "true", "false")
      ```

      ```kusto APL equivalent
      ['dataset.name']
      | extend is_array=isarray(field)
      ```
    </CodeGroup>
  </Accordion>

  <Accordion title="ANSI SQL users">
    In ANSI SQL, there is no built-in function for directly checking if a value is an array. You might need to rely on JSON functions or structural parsing. APL provides the `isarray` function as a more straightforward solution.

    <CodeGroup>
      ```sql SQL example
      SELECT CASE
               WHEN JSON_TYPE(field) = 'ARRAY' THEN TRUE
               ELSE FALSE
             END AS is_array
      FROM dataset_name;
      ```

      ```kusto APL equivalent
      ['dataset.name']
      | extend is_array=isarray(field)
      ```
    </CodeGroup>
  </Accordion>
</LanguageComparisons>