PHP regular expressions (7 common examples) _ PHP Tutorial

PHP regular expressions (seven common examples ). PHP regular expression (7 common examples) 1. verify that using filer_var in E-mail is better than using regular expression matching if (filter_var (test + email @ ansoncheung, FILTER_VALIDATE_EMAIL )) {echoYouremaili PHP regular expression (seven common examples)

1. verify email

Filer_var is better than regular expression matching.

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

2. verify the user name (between 5-20 verified user names)

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

3. verify the IP address

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

4. verify the ZIP code

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

5. verify the domain name

$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."; }

6. extract domain names from a specific URL

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

7. highlight keywords in text

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

Token (seven common examples) 1. verify that using filer_var in E-mail is better than regular expression matching if (filter_var (test + email @ ansoncheung, FILTER_VALIDATE_EMAIL )) {echo Your email I...