WP: removing p

<?php
 
add_filter("the_content", "the_content_filter");
 
function the_content_filter($content) {
 
// array of custom shortcodes requiring the fix
$block = join("|",array("col","shortcode2","shortcode3"));
 
// opening tag
$rep = preg_replace("/(<p>)?\[($block)(\s[^\]]+)?\](<\/p>|<br \/>)?/","[$2$3]",$content);
// closing tag
$rep = preg_replace("/(<p>)?\[\/($block)](<\/p>|<br \/>)?/","[/$2]",$rep);
 
return $rep;
 
}