array_slice()
array_slice() is a PHP native function that extracts a portion of an array.
array_slice() takes the array $array, starts at the offset $offset and collects $length elements. Then it returns the array.
$offset is the position of the index in the array, not the key itself. As usual, it starts at 0. String keys, arbitrary keys, or arbitrary order of the inserted values are ignored: consider that array_slice() works on the result of array_values(). Use sorting beforehand to ensure the key order is taken into account, when needed.
array_slice() also offers a parameter $preserve_keys, which keeps the original keys: only string keys are preserved, integer keys are reindexed, starting at 0. It is disabled by default.
The complement function is array_splice(), which extracts an array from another, and keeps the external portions.
<?php
// simple example
$array = [1, 2, 3, 4,];
print_r(array_slice($array, 1, 2));
// [2, 3]
// use null to reach the end of the array
print_r(array_slice($array, 2, null));
// [3, 4]
// with keys
$array = ['a' => 1, 3 => 2, 3, -1 => 4,];
print_r(array_slice($array, 1, 2));
// [2, 3]
// with preserve_keys
$array = ['a' => 1, 'd' => 2, 5 => 3, -1 => 4,];
print_r(array_slice($array, 1, 2, true));
// ['d' => 2, 0 => 3]
?>