PHP에서 이메일과 IP 주소를 확인하는 방법

public static function isEmail( $email ) 
{ 
return preg_match("/^([a-z0-9]*[-_＼.]?[a-z0-9]+)*@([a-z0-9]*[-_]?[a-z0-9]+)+[＼.][a-z]{2,4}([＼.][a-z]{2})?$/i" , $email ); 
} 
public static function isNumber( $num ) 
{ 
return is_numeric( $num ); 
} 
public static function isUrl( $url , $preg = false ) 
{ 
if( $preg ) 
{ 
$status = preg_match ( "/^([^:＼/＼/])+＼:＼/＼/[＼w-]+＼.[＼w-.＼?＼/]+$/" , $url ); 
} 
else 
{ 
$status = filter_var( $url , FILTER_VALIDATE_URL ); 
} 
return $status; 
}

$email = 'fengdingbo@gmail.com';             
$result = filter_var($email, FILTER_VALIDATE_EMAIL); 
var_dump($result); // string(20) "fengdingbo@gmail.com"

$url = "http://www.jb51.net"; 
$result = filter_var($url, FILTER_VALIDATE_URL); 
var_dump($result); // string(25) "http://www.jb51.net"

$url = "192.168.1.110"; 
$result = filter_var($url, FILTER_VALIDATE_IP); 
var_dump($result); // string(13) "192.168.1.110" 
// 该方法也可以用来验证ipv6。 
$url = "2001:DB8:2de::e13";              
$result = filter_var($url, FILTER_VALIDATE_IP); 
var_dump($result); // string(17) "2001:DB8:2de::e13"