@lang:at

Access an element by index in an array.

Returns: any

Syntax

@lang:at(value index)

Arguments

Name	Type	Description
`value`	`array`	Source array
`index`	`number`	Zero-based index (negative counts from the end)

On-chain face (@at!)

Select one element of the array return of a call through a typed nav step, on-chain. Negative indexes stay negative for dynamic arrays and resolve from the end at assertion time; fixed-size arrays resolve (and bounds-check) them at build time.

Examples

load lang

set $safe 0x44fA8E6f47987339850636F88629646662444217

# The second owner
assert @at!($safe::{getOwners()(address[])} 1) == @me

# The last owner, resolved against the live length
assert @at!($safe::{getOwners()(address[])} -1) == @me

Notes

Works on any element type the word machine or the string faces can judge (single words, and string/bytes elements as their envelopes); struct or nested-array elements need a deeper lens instead.
A lens on the call selects WHICH array first: @at!($c::{config()(uint256,address[])}[_ $] 0).
An out-of-range index reverts with an index error at assertion time.
Over a NESTED ARRAY FACE (@at!(@sort!(…) 0), @at!(@safe:owners!() -1)) the element is a core pick into the live words payload: an untyped word (negative indexes still count from the end).