@lang:bytes.at

Access a single byte by index in a bytes value.

Returns: bytes

Syntax

@lang:bytes.at(value index)

Arguments

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

See Also

• @bytes.slice — extract a byte range
• @at — array element access

On-chain face (@bytes.at!)

A one-byte slice of the bytes/string return of a call: the @str.at! recipe with the Bytes category. A negative index compiles to sub(byteLen(s), k) so it resolves against the live byte length at assertion time.

Examples

load lang

set $oracle 0x44fA8E6f47987339850636F88629646662444217

# The version byte leads the blob
assert @bytes.at!($oracle::{blob()(bytes)} 0) == 0x01

# The checksum byte trails it, resolved against the live length
assert @bytes.at!($oracle::{blob()(bytes)} -1) == 0xff

Notes

• An out-of-range index reverts at assertion time (SliceOutOfBounds) — on-chain slicing has no silent clamp.

See Also

• assert, @bytes.slice!, @str.at!