Online PHP editor | output for HG7uH

<?php $data = <<<DATA <a> <a1> <author pid = "123"> </author> <book>Book1</book> </a1> <a1> <author pid = "123"> </author> <book>Book1</book> </a1> <a2> <editor pid = "123"> </editor> <book>Book2</book> </a2> </a> DATA; $abc= new DomDocument(); $abc->loadXML($data); $xpath = new DOMXPath($abc); $venue = "Book1"; $expr = "/a/*[self::a1 or self::a2]/*[self::author or self::editor][@pid=\"123\"]/following-sibling::book[normalize-space(text()) = '" . $venue . "']"; $xyz = $xpath->query($expr); echo $xyz->length;