Remove a child with a specific attribute, in SimpleXML for PHP

Question

I have several identical elements with different attributes that I\'m accessing with SimpleXML:

Answer 1

To remove/keep nodes with certain attribute value or falling into array of attribute values you can extend SimpleXMLElement class like this (most recent version in my GitHub Gist):

class SimpleXMLElementExtended extends SimpleXMLElement
{    
    /**
    * Removes or keeps nodes with given attributes
    *
    * @param string $attributeName
    * @param array $attributeValues
    * @param bool $keep TRUE keeps nodes and removes the rest, FALSE removes nodes and keeps the rest 
    * @return integer Number o affected nodes
    *
    * @example: $xml->o->filterAttribute('id', $products_ids); // Keeps only nodes with id attr in $products_ids
    * @see: http://stackoverflow.com/questions/17185959/simplexml-remove-nodes
    */
    public function filterAttribute($attributeName = '', $attributeValues = array(), $keepNodes = TRUE)
    {       
        $nodesToRemove = array();

        foreach($this as $node)
        {
            $attributeValue = (string)$node[$attributeName];

            if ($keepNodes)
            {
                if (!in_array($attributeValue, $attributeValues)) $nodesToRemove[] = $node;
            }
            else
            { 
                if (in_array($attributeValue, $attributeValues)) $nodesToRemove[] = $node;
            }
        }

        $result = count($nodesToRemove);

        foreach ($nodesToRemove as $node) {
            unset($node[0]);
        }

        return $result;
    }
}

Then having your $doc XML you can remove your node calling:

$data='
    
    
    
    
    
';

$doc=new SimpleXMLElementExtended($data);
$doc->seg->filterAttribute('id', ['A12'], FALSE);

or remove multiple nodes:

$doc->seg->filterAttribute('id', ['A1', 'A12', 'A29'], FALSE);

For keeping only and nodes and removing the rest:

$doc->seg->filterAttribute('id', ['A5', 'A30'], TRUE);