Online PHP editor | output for Iajsp

<?php $area_codes = array( '015019', '015020', '01511', '01512', '01514', '01515', '01516', '01517', '015180', '015181', '015182', '015183', '015184', '015185', ); // Build an associative array $area_lookup = []; foreach($area_codes as $code) $area_lookup[$code] = 1; function splitNumber(array $area_lookup, string $telephone_number): array { for($len=4;$len<=6;$len++) { $prefix = substr($telephone_number, 0, $len); if(isset($area_lookup[$prefix])) return ['area_code' => $prefix, 'subscriber_number' => substr($telephone_number, $len)]; } throw new Exception('Invalid number'); } $res1 = splitNumber($area_lookup, '015169999999'); $res2 = splitNumber($area_lookup, '015180999999'); var_dump($res1, $res2);