Regex to parse Email Form "To" field

Question

If there is one that could handle this, what would be the correct regex pattern to extract email addresses from a string coming from an email form "To" line, that allows the addresses to be delimited by commas ",", semicolons ";", spaces, or any combination of the three. The regex also has to be able to ignore "noise" text, such as if an address is enclosed in "<" and ">" characters, or has an actual name next to the email address. For example, from this string that was in the To field:

"Joe Smith" <[email protected]>, [email protected]; [email protected] [email protected]

The pattern should be able to return the following matches of: jsmith@example, [email protected], [email protected], [email protected]

I am using PHP, so if this can't be done in single regex then im definitely open to other PHP-based solutions.

Thanks

Answer 1

Try

\b[A-Z0-9._%+-]+@(?:[A-Z0-9-]+\.)+[A-Z]{2,6}\b

(courtesy of RegexBuddy) as in

preg_match_all('/\b[A-Z0-9._%+-]+@(?:[A-Z0-9-]+\.)+[A-Z]{2,6}\b/i', $subject, $result, PREG_PATTERN_ORDER);
$result = $result[0];

Note the /i modifier to make it case-insensitive.

See also this question for an explanation of the drawbacks of regexes for finding e-mail addresses in a string.

Answer 2

I got the regex from http://www.webcheatsheet.com/php/regular_expressions.php, and only modified it slightly.

$string = '"Joe Smith" <[email protected]>, [email protected]; [email protected] [email protected]';
$email_regex = "/[^0-9< ][A-z0-9_]+([.][A-z0-9_]+)*@[A-z0-9_]+([.][A-z0-9_]+)*[.][A-z]{2,4}/";
preg_match_all($email_regex, $string, $matches);
$emails = $matches[0];

Now $emails will have an array with all your email addresses.