3v4l.org

run code in 300+ PHP versions simultaneously
<?php $arr = [ 'foo', 'foo', 'bar', 'baz', 'baz' ]; array_walk($arr, function (&$item, $k) use ($arr) { $lower = mb_strtolower($item, 'utf-8'); foreach ($arr as $i => $v) { var_dump($k .'='. $i); if ($i !== $k && $v !== null && $lower === mb_strtolower($v, 'utf-8')) { var_dump('rm'); $item = null; } } }); var_dump($arr);

preferences:
31.31 ms | 402 KiB | 5 Q