The DOMNodeList class

ignitedfirestarter at gmail dot com (2012-07-04 10:39:50)

If you want to recurse over a DOM then this might help: 
<?php 

/**
 * PHP's DOM classes are recursive but don't provide an implementation of 
 * RecursiveIterator. This class provides a RecursiveIterator for looping over DOMNodeList
 */
class DOMNodeRecursiveIterator extends ArrayIterator implements RecursiveIterator {
  
  public function __construct (DOMNodeList $node_list) {
    
    $nodes = array();
    foreach($node_list as $node) {
      $nodes[] = $node;
    }
    
    parent::__construct($nodes);
    
  }
  
  public function getRecursiveIterator(){
    return new RecursiveIteratorIterator($this, RecursiveIteratorIterator::SELF_FIRST);
  }
  
  public function hasChildren () {
    return $this->current()->hasChildNodes();
  }

  
  public function getChildren () {
    return new self($this->current()->childNodes);
  }
  
}
?>

geompse at gmail dot com (2010-05-19 08:39:58)

Note that $length is calculated (php5.3.2).
Iterating over a large NodeList may be time expensive.
Prefer :
$nb = $nodelist->length;
for($pos=0; $pos<$nb; $pos++)
Than:
for($pos=0; $pos<$nodelist->length; $pos++)
I had a hard time figuring that out...

nascoedu (2008-09-18 15:44:40)

Get some nodes from an existing xml file and add them to a new file:

<?php
$dom = new DOMDocument;
$dom->load($xmlsource);

/*create the xPath object _after_  loading the xml source, otherwise the query won't work:*/
$xPath = new DOMXPath($dom);

/*now get the nodes in a DOMNodeList:*/
$nodeList = $xPath->query($anXPathExpr);

/*create a new DOMDocument and add a root element:*/
$newDom = new DOMDocument('1.0','UTF-8');
$root = $newDom->createElement('root');
$root = $newDom->appendChild($root);

/* append all nodes from $nodeList to the new dom, as children of $root:*/
foreach ($nodeList as $domElement){
   $domNode = $newDom->importNode($domElement, true);
   $root->appendChild($domNode);
}
/*please note: importNode does not cast a DOMElement to a DOMNode!*/

/*save the new dom */
echo 'Wrote: ' . $newDom->save('newDOM.xml') . ' bytes';
?>

the following won't work and you'll end up with a DOMException: 'Wrong Document Error' (at least I did):

<?php
foreach ($nodeList as $element){
   $root->appendChild($element);
}
?>

Cheers! ;-)
---
WindowsXP, WAMP5 (appache 2.2.6), PHP 5.2.5, DOM/XML API Version 20031129, libxml 2.6.26
---

c dot 1 at smithies dot org (2008-08-27 15:26:49)

I doubt the accuracy of what saad105050 wrote below. In particular, in his example, he seems to assume that $element->getElementsByTagName() will return NULL if there are no matching nodes. This is not what happens; as per the documentation, a DOMNodeList is returned with the length property zero.

bobvandell at hotmail dot com (2008-08-26 09:12:01)

That's actually incorrect. You can use function results as objects. It makes building an API for your database very clean and neat. For example:
Our code:
$articles = Node::screate('tags', 123456)->assets('like:title:test')->articles;
We use the above code to get articles that are linked to assets that are linked to a specific tag in our database.

c dot 1 at smithies dot org (2008-05-23 05:43:49)

You can modify, and even delete, nodes from a DOMNodeList if you iterate backwards:
$els = $document->getElementsByTagName('input');
for ($i = $els->length; --$i >= 0; ) {
$el = $els->item($i);
switch ($el->getAttribute('name')) {
case 'MAX_FILE_SIZE' :
$el->parentNode->removeChild($el);
break;
case 'inputfile' :
$el->setAttribute('type', 'text');
//break;
}
}

drichter at muvicom dot de (2008-05-14 06:11:58)

Addition to my first note:
An traditional for-loop does not allow you to change the DOM-tree while looping - the effects are the nearly the same as with foreach. So you have to collect the nodes in an array and do the tree-altering stuff within a second loop (looping the array this time ...)

drichter at muvicom dot de (2008-05-14 04:56:18)

I have done some testing and have found 2 results:
(My System: Win XP with PHP 5.2.1)
1) Iteration with foreach does function correctly as "james dot j dot hackett at gmail dot com" writes, _if_ you only do readonly stuff with foreach or minor writings of some attributes.
2) foreach does not function, if you are doing some DOM-Operations while iterating. In my situation it was adding the iterated $node as an child to an new node:
$newNode = $dom->createElement('newNode') ;
foreach ($nodeList as $node) {
echo $node->nodeValue ;
$newNode->appendChild($node) ;
}
This only gives you the first element ...
I'm interpreting it as an confusing but correct behavior because of the changes within the $dom-object while appending the node at an additional place ...
So, if you want to do something like 2) use for, length and item() :)

james dot j dot hackett at gmail dot com (2008-05-08 09:47:49)

In Response to 'kassah at gmail'
You don't need to convert a DOMNodeList to an array in order iterate through it using 'foreach'. You can use foreach directly with the DOMNodeList.
$nodeList = $someDomDocument->getElementsbytagname('user');
foreach ($nodeList as $node) {
echo $node->nodeValue;
}

kassah at gmail dot com (2008-05-04 17:06:41)

// Converts a DOMNodeList to an Array that can be easily foreached
function dnl2array($domnodelist) {
$return = array();
for ($i = 0; $i < $domnodelist->length; ++$i) {
$return[] = $domnodelist->item($i);
}
return $return;
}

brack at wjp dot de (2008-04-21 02:35:26)

In PHP 5.2.5 (Windows) it is not possible to iterate correctly over the DOMNodeList object returned by DOMNode->childNodes using foreach. Instead I had to use the for loop in conjunction with the item() method of DOMNodeList for iterating over all child nodes correctly.
I don't know whether this is really a bug, but apparently it is.