How to remove entire div with preg_replace

Question

Ok, as it is WordPress problem and it sadly goes a little deeper, I need to remove each representation of parent div and its inside:

Answer 1

I wouldn't use a regular expression. Instead, I would use the DOMDocument class. Just find all of the div elements with that class, and remove them from their parent(s):

$html = "
Hello World
         

           
           
Bar
         
";

$dom = new DOMDocument;
$dom->loadHTML( $html );

$xpath = new DOMXPath( $dom );
$pDivs = $xpath->query(".//div[@class='sometestclass']");

foreach ( $pDivs as $div ) {
  $div->parentNode->removeChild( $div );
}

echo preg_replace( "/.*(.*)<\/body>.*/s", "$1", $dom->saveHTML() );

Which results in:

Hello World