Mailbox regular expression implementation code (for php)

/**
* Email address regular expression
 */
$preg = '/^(\w{1,25})@(\w{1,16})(\.(\w{1,4})){1,3}$/';
$b = 'ffgddayasdadasdf@';
if(preg_match($preg, $b)){
echo "Matched";
}else{
echo "No match";
}