# Array.at

## Function

Read array elements by subscript, and support negative numbers in reverse reading from the end of the array.

## Syntax

```bt
array.at(index)
```

## Parameters

| Parameters | Type | Required | Default value | Description |
| ------ | ------ | ------ | ------ | ------ |
| index | Int | No | 0 | Element index; negative numbers count backwards from the end. |

## Return value

| Type | Description |
| ------ | ------ |
| Any/Empty | The corresponding element is returned when the subscript is valid, and Empty is returned when it is out of bounds. |

## Example

```bt
items = ['a', 'b', 'c']
result = items.at(-1)

// Output: c
print result
```

## Notes

- at does not modify the original array.
- when reading the last element, at(-1) requires one less array allocation than slice(-1)[0].