DOMNodeList::item

(PHP 5, PHP 7)

DOMNodeList::item Получает узел с заданным индексом

Описание

DOMNode DOMNodeList::item ( int $index )

Извлекает узел с заданным индексом index из объекта класса DOMNodeList.

Подсказка

Если требуется узнать количество узлов в коллекции, используйте свойство length объекта класса DOMNodeList.

Список параметров

index

Индекс узла в коллекции.

Возвращаемые значения

Узел, находящийся в позиции index объекта DOMNodeList, или NULL, если этот индекс недопустим.

Примеры

Пример #1 Вывод содержимого таблицы

<?php

$doc 
= new DOMDocument;
$doc->load('book.xml');

$items $doc->getElementsByTagName('entry');

for (
$i 0$i $items->length$i++) {
    echo 
$items->item($i)->nodeValue "\n";
}

?>

Кроме того, можно воспользоваться foreach;, что будет намного удобнее:

<?php

foreach ($items as $item) {
    echo 
$item->nodeValue "\n";
}

?>

Результат выполнения данного примера:

Title
Author
Language
ISBN
The Grapes of Wrath
John Steinbeck
en
0140186409
The Pearl
John Steinbeck
en
014017737X
Samarcande
Amine Maalouf
fr
2253051209

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User Contributed Notes 9 notes

up
3
Anonymous
6 years ago
calling domnodelist->item($i) with an index $i greater than domnodelist->length - 1 , will return the entire document, will not produce an error, and will not circle back to the start of the list.
up
2
Nagy Attila
7 years ago
DOMNodeList::item does not return in constant time!

If you need to iterate over large nodelist then you'd better use standard navigation.

Instead of:

<?php
foreach ($nodelist as $node) {
   
// do something
}
?>

you could do:

<?php
$node
= $parentnode->firstChild;

do {
   
// do something
} while ($node = $node->nextSibling);
?>
up
2
vinyanov at poczta dot onet dot pl
10 years ago
SimpleXML has its own SPL iterator. See http://www.php.net/~helly/php/ext/spl/classSimpleXMLIterator.html . But I guess that there are none for DOM nodes. By the way, two out of three implementations I found over the Net were not recursive, so I wrote my own. Here is the snippet:

<?php

class DOMNodeListIterator implements RecursiveIterator
{
    private
       
$nodes,
       
$offset;

    function
__construct(DOMNodeList $nodes)
    {
        return
$this -> nodes = $nodes;
    }
   
    function
rewind()
    {
        return
$this -> offset = 0;
    }
   
    function
current()
    {
        return
$this -> nodes -> item($this -> offset);
    }

    function
key()
    {
        return
$this -> current() -> nodeName;
    }
   
    function
next()
    {
        return
$this -> offset++;
    }
   
    function
valid()
    {
        return
$this -> offset < $this -> nodes -> length;
    }
   
    function
hasChildren()
    {
        return isset(
$this -> current() -> childNodes -> length) && $this -> current() -> childNodes -> length > 0;
    }
   
    function
getChildren()
    {
        return new
self($this -> current() -> childNodes);
    }
}

?>

Remember to use RecursiveIteratorIterator::SELF_FIRST flag when you create your iterator iterator.

<?php

$iterator
= new DOMNodeListIterator($document -> childNodes);
$iterator = new RecursiveIteratorIterator($iterator, RecursiveIteratorIterator::SELF_FIRST);

?>

Should work, has just few minutes though. :)
up
1
Geoffrey Thubron
11 years ago
@ tfg_allardyce at gmail dot com

You could loop through the list backwards, that way, you are only ever taking off the last item from the list, and hence wont have disrupted the order.
up
0
jeffpuckett2 at gmail dot com
2 years ago
DOMNodelist::item can return a DOMElement object, which extends DOMNode class. But it can also return a DOMText object.

<?php
$xml
= '
<root>
  <node/>
  <node>
    <sub>more</sub>
  </node>
  <node>
    <sub>another</sub>
  </node>
  <node>value</node>
</root>
'
;

$doc = new DOMDocument();
$doc->loadXML($xml);

$items = $doc->documentElement->childNodes;
for (
$i = 0; $i < $items->length; $i++)
  echo
get_class($items->item($i)).PHP_EOL;
?>

Results in this output:

DOMText
DOMElement
DOMText
DOMElement
DOMText
DOMElement
DOMText
DOMElement
DOMText
up
0
olivier dot berger at it-sudparis dot eu
10 years ago
It seems that with zend.ze1_compatibility_mode on, the only way to iterate over the items list is with :
for ($i = 0; $i < $nodeList->length; ++$i) {
    $nodeName = $nodeList->item($i)->nodeName;
    $nodeValue = $nodeList->item($i)->nodeValue;
}

As other attemps failed :

for ($i = 0; $i < $nodeList->length; ++$i) {
    $node = &$nodeList->item($i);
    $nodeName = $node->nodeName;
    $nodeValue = $node->nodeValue;
}

or :
foreach ($nodeList as $node) {
    echo $node->nodeName;
    echo $node->nodeValue;
}
up
0
Hayley Watson
10 years ago
Keep in mind that DOMNodelists are "live" - changes to the document or node that the DOMNodelist was derived from will be reflected in the DOMNodelist. In other words, a list of a parent node's children will change if you change the parent's children!
up
0
james dot dunmore at gmai dot com
11 years ago
tfg_allardyce at gmail dot com

I have had exactly this problem.

To rectify I've had to do this:
<?php
$old_element
= $doc->getElementsByTagName('Element1')->item(0);
$new_element = $doc->createElement('NewElement1');

$old_element_childNodes = $old_element->childNodes;
$length = $old_element_childNodes->length;

for(
$i = 0; $i < $length; $i++)
{       
   
$oldChildren_array[] = $old_element_childNodes->item($i);
}

foreach(
$oldChildren_array as $old_c)
{
   
$new_element->appendChild($old_c);
}
?>

Rather than this:
(which I will bug report)
<?php
$old_element
= $doc->getElementsByTagName('Element1')->item(0):
$new_element = $doc->createElement('NewElement1');

foreach(
$old_element->childNode as $node)
{
    
$new_element->appendChild($node);
}

?>

Using the latter, randomally removes the children!
up
0
oliver dot christen at camptocamp dot com
11 years ago
NodeList are something annoying because you can't output the content with a simple print_r, so I did a little function that add all the node to a new empty DOMDocument and output it as a string.
Have fun.

<?php

public function domNodeList_to_string($DomNodeList) {
   
$output = '';
   
$doc = new DOMDocument;
    while (
$node = $DomNodeList->item($i) ) {
       
// import node
       
$domNode = $doc->importNode($node, true);
       
// append node
       
$doc->appendChild($domNode);
       
$i++;
    }
   
$output = $doc->saveXML();
   
$output = print_r($output, 1);
   
// I added this because xml output and ajax do not like each others
   
$output = htmlspecialchars($output);
    return
$output;
}

?>
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