How to get email address from a long string

Building on mandaleeka's answer, break the string up using a space delimeter then use filter_var to sanitize then validate to see if what remains is a legitimate email address:

function extract_email_address ($string) {
    foreach(preg_split('/\s/', $string) as $token) {
        $email = filter_var(filter_var($token, FILTER_SANITIZE_EMAIL), FILTER_VALIDATE_EMAIL);
        if ($email !== false) {
            $emails[] = $email;
        }
    }
    return $emails;
}

If you're not sure which part of the space-separated string is the e-mail address, you can split the string by spaces and use

filter_var($email, FILTER_VALIDATE_EMAIL)

on each substring.

based from constantine regex.. works with ip address domain too.

$pattern="/(?:[A-Za-z0-9!#$%&'*+=?^_`{|}~-]+(?:\.[A-Za-z0-9!#$%&'*+=?^_`{|}~-]+)*|\"(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])*\")@(?:(?:[A-Za-z0-9](?:[A-Za-z0-9-]*[A-Za-z0-9])?\.)+[A-Za-z0-9](?:[A-Za-z0-9-]*[A-Za-z0-9])?|\[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[A-Za-z0-9-]*[A-Za-z0-9]:(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21-\x5a\x53-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])+)\])/";

//$pattern="/[A-Za-z0-9_-]+@[A-Za-z0-9_-]+\.([A-Za-z0-9_-][A-Za-z0-9_]+)/";

$subject="Hello [email protected] francis a@b words [email protected] words 2 words123 [email protected]";


preg_match_all($pattern, $subject, $matches);