Die zehn praktischsten regulären PHP-Ausdrücke

if (filter_var('test+email@ansoncheung', FILTER_VALIDATE_EMAIL)) {  
echo "Your email is ok.";  
} else {  
echo "Wrong email address format.";  
}

$username = "user_name12";  
if (preg_match('/^[az\d_]{5,20}$/i', $username)) {  
echo "Your username is ok.";  
} else {  
echo "Wrong username format.";  
}

$phone = "(021)4232323";  
if (preg_match('/?\d3?[\s.]?\d{3}[\s.]\d{4}/x', $phone)) {  
echo "Your phone number is ok.";  
} else {  
echo "Wrong phone number.";  
}

$IP = "198.168.1.78";  
if   
(preg_match('/^(([19]?[09]|1[09]{2}|2[04][09]|25[05]).){3}([19]?[09]|1[09]{2}|2[04][09]|25[05])$/',$IP))   
{  
echo "Your IP address is ok.";  
} else {  
echo "Wrong IP address.";  
}

$zipcode = "123455434";  
if (preg_match("/^([09]{5})([09]{4})?$/i",$zipcode)) {  
echo "Your Zip code is ok.";  
} else {  
echo "Wrong Zip code.";  
}

$ssn = "333232329";  
if (preg_match('/^[\d]{3}[\d]{2}[\d]{4}$/',$ssn)) {  
echo "Your SSN is ok.";  
} else {  
echo "Wrong SSN.";  
}

$cc = "378282246310005";  
if   
(preg_match('/^(?:4[09]{12}(?:[09]{3})?|5[15][09]{14}|6011[09]{12}|3(?:0[05]|[68][09])[09]{11}|3[47][09]{13})$/',   
$cc)) {  
echo "Your credit card number is ok.";  
} else {  
echo "Wrong credit card number.";  
}

$url = "http://ansoncheung.tk/";  
if   
(preg_match('/^(http|https|ftp):\/\/([AZ09][AZ09_](?:\.[AZ09][AZ09_])+):?(\d+)?\/?/i',   
$url)) {  
echo "Your url is ok.";  
} else {  
echo "Wrong url.";  
}

4$url = "http://ansoncheung.tk/articles";  
preg_match('@^(?:http://)?([^/]+)@i', $url, $matches);  
$host = $matches[1];  
echo $host;

$text = "Sample sentence from AnsonCheung.tk, regular expression has become   
popular in web programming. Now we learn regex. According to wikipedia, Regular   
expressions (abbreviated as regex or regexp, with plural forms regexes, regexps,   
or regexen) are written in a formal language that can be interpreted by a   
regular expression processor";  
$text = preg_replace("/\b(regex)\b/i", '\1', $text);  
echo $text;