PHP implements regular expression extraction email address function

function extract_emails_from($string) {
 //Add judgment on #, you know this ^_^ http://blog.ddian.cn
 preg_match_all("/[._a-zA-Z0-9 -]+(@|#)[._a-zA-Z0-9-]+/i", $string, $matches);
 return $matches[0];
}

Regular expressions, PHP, email