Online PHP editor | refs for sp8Eh

<?php $numbers = [1, 2, 3, 4, 5, 6, 7, 11, 21, 22, 23, 24]; $numbers = [1, 3, 5, 6, 11, 21, 22, 23, 24, 26]; $prev = -1; foreach ($numbers as $n) { if (!isset($start)) { $start = $n; } elseif ($n != $prev + 1) { $result[] = $start == $prev ? $prev : "$start-$prev"; $start = $n; } $prev = $n; } $result[] = $start == $prev ? $prev : $start . '-' . $prev; echo implode(', ', $result);