Slice

:::info[Note] This is a point-in-time snapshot of the API documentation from January 2026. Going forward, we will not be maintaining a public copy of these references, and recommend users to refer to the built-in signature helpers available in the Hack LSP instead for complete and up-to-date information. :::

Returns a subset of the current MutableVector starting from a given key up to, but not including, the element at the provided length from the starting key

public function slice(
  int $start,
  int $len,
): MutableVector<Tv>;

$start is 0-based. $len is 1-based. So slice(0,2) would return the elements at key 0 and 1.

The returned MutableVector will always be a proper subset of this MutableVector.

Parameters

• int $start - The starting key of this Vector to begin the returned MutableVector.
• int $len - The length of the returned MutableVector.

Returns

• MutableVector<Tv> - A MutableVector that is a proper subset of the current MutableVector starting at $start up to but not including the element $start + $len.