How do I delete nodes from an XML document using SimpleXML and DOMDocument in PHP?

Deleting Nodes in SimpleXML

Querying XPath Nodes

To delete a node in SimpleXML using XPath, follow these steps:

1. Load the XML document into a SimpleXMLElement object.
2. Use the xpath() method to search for the desired node.
3. Store the result in a variable, e.g., $data.

Node Removal

To remove the parent node of the selected node, you cannot use unset($parent). Instead, you need to use the __unset() method or revert to DOMDocument.

Using __unset()

The __unset() method is called when you try to unset a property of an object. To remove a node using __unset(), create a new SimpleXMLElement object and unset the desired node, as shown below:

<code class="php">$newNode = new SimpleXMLElement('<a><b></b></a>');
unset($newNode->b);
echo $newNode->asxml(); // Prints <a></a></code>

Using DOMDocument

DOMDocument provides more detailed control over XML manipulation. To remove a node using DOMDocument:

1. Create a new DOMDocument object and load the XML document.
2. Use the xpath() method to search for the desired node.
3. Remove the node using parentNode->removeChild($node).

Example with DOMDocument

<code class="php">$doc = new DOMDocument;
$doc->loadxml('<foo><items><info><item_id>123</item_id></info></items></foo>');
$item_id = 123;

$xpath = new DOMXpath($doc);
foreach ($xpath->query('//items[info/item_id="' . $item_id . '"]') as $node) {
  $node->parentNode->removeChild($node);
}
echo $doc->savexml(); // Prints <foo><items><info><item_id>123</item_id></info></items></foo></code>

By using these techniques, you can effectively remove nodes from XML documents using SimpleXML and DOMDocument.

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