HH\Vector::slice
Returns a subset of the current Vector 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,
): Vector<Tv>;
$start is 0-based. $len is 1-based. So slice(0,2) would return the
elements at keys 0 and 1.
The returned Vector will always be a subset (but not necessarily a
proper subset) of the current Vector. If $start is greater than or
equal to the length of the current Vector, the returned Vector will
contain no elements.  If $start + $len is greater than or equal to the
length of the current Vector, the returned Vector will contain the
elements from $start to the end of the current Vector.
If either $start or $len is negative, an exception is thrown.
Parameters
int $start- The starting key of the currentVectorat which to begin the returnedVector.int $len- The length of the returnedVector.
Returns
Vector<Tv>- AVectorthat is a subset of the currentVectorstarting at$startup to but not including the element$start + $len.
Examples
$v = Vector {'red', 'green', 'blue', 'yellow'};
// Start at index 1 ('green') and include 3 elements
$v2 = $v->slice(1, 3);
\var_dump($v2);