---
title: Array Built-ins
sidebar_label: Arrays
---
<BuiltinTable category={"array"}/>

## Examples

### `array.concat`

`array.concat` returns a new array with the elements of the second array
appended to the first. Policies use it to extend a base list — for example
default registries or hosts — with extra values from input or data.

<PlaygroundExample dir={require.context('../_examples/array/concat/merge-allowlists')} />
