Online PHP editor | output for StFn7

<?php function highlight(string $search, string $number) { $searchBegin = NULL; $searchIndex = 0; $search = str_replace([',', '.'], '', $search); foreach (str_split($number) as $numberIndex => $character) { if ($character == $search[$searchIndex]) { if (is_null($searchBegin)) { $searchBegin = $numberIndex; } $searchIndex++; if ($searchIndex == strlen($search)) { return substr($number, 0, $searchBegin) . '<span style="background: yellow">' . substr($number, $searchBegin, $numberIndex - $searchBegin + 1) . '</span>' . substr($number, $numberIndex +1); } } elseif (!in_array($character, [',', '.'])) { $searchBegin = NULL; $searchIndex = 0; } } return $number; } echo highlight('4321', '12,345,678.00') . PHP_EOL; echo highlight('1234', '12,345,678.00') . PHP_EOL; echo highlight('4567', '12,345,678.00') . PHP_EOL; echo highlight('3,456', '12,345,678.00') . PHP_EOL; echo highlight('7.80', '12,345,678.00') . PHP_EOL;