3v4l.org

run code in 300+ PHP versions simultaneously
<?php $array = [10, -1, -1, -1, -1, 15, 16, 17, -1, -1, 20]; $result = []; foreach ($array as $v) { if ($v === -1) { unset($ref); continue; } if (!isset($ref)) { $result[] =& $ref; } $ref[] = $v; } var_export($result);
Output for 8.1.0 - 8.1.34, 8.2.0 - 8.2.30, 8.3.0 - 8.3.30, 8.4.1 - 8.4.18, 8.5.0 - 8.5.3
array ( 0 => array ( 0 => 10, ), 1 => array ( 0 => 15, 1 => 16, 2 => 17, ), 2 => array ( 0 => 20, ), )

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51.26 ms | 988 KiB | 4 Q