3v4l.org

run code in 300+ PHP versions simultaneously
<?php $in = [ '2,24', '2,2,9,12' ]; $out = []; foreach($in as $item) { $norm = explode(',', $item); $ar = array_count_values($norm); $pos = []; $out[] = &$pos; array_walk($ar, function ($val, $key) use(&$pos) { if($val > 1) { $pos[] = $key . '(' . $val . ')'; } else { $pos[] = $key; } }); unset($pos); } foreach($out as $listItem) { echo implode(',', $listItem) , PHP_EOL; }

preferences:
50.14 ms | 402 KiB | 5 Q