extract emails "PHP"

> function extract_emails($str){
// This regular expression extracts all emails from
// a string:
$regexp = /([a-z0-9_\.\-])+\@(([a-z0-9\-])+\.)+([a-z0-9]{2,4})+/i
preg_match_all($regexp, $str, $m);

return isset($m[0]) ? $m[0] : array();
}

$test_string = This is a test string...

test1@example.org


Test different formats:
test2@example.org;
foobar



strange formats:
test5@example.org
test6[at]example.org
test7@example.net.org.com
test8@ example.org
test9@!foo!.org

foobar


print_r(extract_emails($test_string));