3v4l.org

run code in 300+ PHP versions simultaneously
<?php $array = [1, 2, 3, 4, 5, 6, 7, 8, 9]; foreach ($array as $i => $v) { $group = (int) ($i / 4); if (isset($result[$group])) { $result[$group] .= ", $v"; } else { $result[$group] = "$v"; } } var_export($result);
Output for 7.4.0 - 7.4.33, 8.0.1 - 8.0.30, 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.25, 8.4.1 - 8.4.12
array ( 0 => '1, 2, 3, 4', 1 => '5, 6, 7, 8', 2 => '9', )
preferences:
82.74 ms | 406 KiB | 5 Q