postcode en huisnr controleren

if
(preg_match( '/^[1-9][0-9]{3} ?[a-z]{2}$/i', trim($_POST['postcode'])))
include("select.php");

else 
echo 'foute postcode'; 

if
(preg_match( '/^[1-9][0-9]{3} ?[a-z]{2}$/i', trim($_POST['postcode'])))
include("select.php");
 
else 
echo 'foute postcode';

ctype_digit($_POST['huisnr']);

ctype_digit($_POST['huisnr']);