$re = '/players\/(.+)-/im';
$str = '<iframe src="//content.jwplatform.com/players/ewQYJ6zA-F6KYzWLn.html" width="480" height="270" frameborder="0" scrolling="auto" allowfullscreen></iframe>';
preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php