Remove empty tags from XML using PHP

Question

Question

How to remove empty xml tags in PHP?

Example:

$value1 = "2"; $value2 = "4"; $value3 = ""; xml = '<parentnode> <tag1> ' .$value1. '</tag1> <tag2> ' .$value2. '</tag2> <tag3> ' .$value3. '</tag3> </parentnode>'; 

XML Result:

 <parentnode> <tag1>2</tag1> <tag2>4</tag2> <tag3></tag3> // <- Empty tag </parentnode> 

What I want!

  <parentnode> <tag1>2</tag1> <tag2>4</tag2> </parentnode> 

XML without empty tags such as "tag3"

Thanks!

Answer 1

You can use XPath with predicate not(node()) to select all elements that do not have child nodes.

 <?php $doc = new DOMDocument; $doc->preserveWhiteSpace = false; $doc->loadxml('<parentnode> <tag1>2</tag1> <tag2>4</tag2> <tag3></tag3> <tag2>4</tag2> <tag3></tag3> <tag2>4</tag2> <tag3></tag3> </parentnode>'); $xpath = new DOMXPath($doc); foreach( $xpath->query('//*[not(node())]') as $node ) { $node->parentNode->removeChild($node); } $doc->formatOutput = true; echo $doc->savexml(); 

prints

 <?xml version="1.0"?> <parentnode> <tag1>2</tag1> <tag2>4</tag2> <tag2>4</tag2> <tag2>4</tag2> </parentnode> 

Answer 2

This works recursively and removes nodes that:

• contain only spaces
• have no attributes
• have no child notes

 // not(*) does not have children elements // not(@*) does not have attributes // text()[normalize-space()] nodes that include whitespace text while (($node_list = $xpath->query('//*[not(*) and not(@*) and not(text()[normalize-space()])]')) && $node_list->length) { foreach ($node_list as $node) { $node->parentNode->removeChild($node); } } 

Answer 3

 $dom = new DOMDocument; $dom->loadXML($xml); $elements = $dom->getElementsByTagName('*'); foreach($elements as $element) { if ( ! $element->hasChildNodes() OR $element->nodeValue == '') { $element->parentNode->removeChild($element); } } echo $dom->saveXML(); 

CodePad

Answer 4

The solution that worked with my working PHP SimpleXMLElement object code using Xpath was as follows:

 /* * Remove empty (no children) and blank (no text) XML element nodes, but not an empty root element (/child::*). * This does not work recursively; meaning after empty child elements are removed, parents are not reexamined. */ foreach( $this->xml->xpath('/child::*//*[not(*) and not(text()[normalize-space()])]') as $emptyElement ) { unset( $emptyElement[0] ); } 

Note that it is not necessary to use PHP DOM, DOMDocument, DOMXPath or dom_import_simplexml ().

 //this is a recursively option do { $removed = false; foreach( $this->xml->xpath('/child::*//*[not(*) and not(text()[normalize-space()])]') as $emptyElement ) { unset( $emptyElement[0] ); $removed = true; } } while ($removed) ; 

Answer 5

If you are going to a lot, just do something like:

 $value[] = "2"; $value[] = "4"; $value[] = ""; $xml = '<parentnode>'; for($i=1,$m=count($value); $i<$m+1; $i++) $xml .= !empty($value[$i-1]) ? "<tag{$i}>{$value[$i-1]}</tag{$i}>" : null; $xml .= '</parentnode>'; echo $xml; 

Ideally, you should probably use domdocument .