PHP正則表達式(常用的7個例子)

PHP正則表達式(常用的7個例子)

1、驗證E-mail

用filer_var 比用正則匹配更加好

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

2、驗證用戶名(驗證用戶名5-20之間)

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

3、驗證ip地址

$IP = "198.168.1.78";
if (preg_match('/^(([1-9]?[0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5]).){3}([1-9]?[0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$/',$IP)) {
    echo "Your IP address is ok.";
} else {
    echo "Wrong IP address.";
}

4、驗證郵編

$zipcode = "12345-5434";
 if (preg_match("/^([0-9]{5})(-[0-9]{4})?$/i",$zipcode)) {
 echo "Your Zip code is ok.";
 } else {
 echo "Wrong Zip code.";
 }

5、驗證域名

$url = "http://ansoncheung.tk/";
 if (preg_match('/^(http|https|ftp):\/\/([A-Z0-9][A-Z0-9_-]*(?:\.[A-Z0-9][A-Z0-9_-]*)+):?(\d+)?\/?/i', $url)) {
 echo "Your url is ok.";
 } else {
 echo "Wrong url.";
 }

$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;