3v4l.org

run code in 500+ PHP versions simultaneously
<?php $str = "&#233333;"; $str = preg_replace_callback( '/\&\#([0-9]+)\;/m', function($matches) { var_dump($matches); return strtoupper($matches[1]); }, $str ); echo $str;

preferences:
45.56 ms | 1533 KiB | 5 Q