Deleting simplexmlelement node [duplicate]

Question

I have an xml file of this structure

<?xml version="1.0" encoding="iso-8859-1"?> <my_events> <event id="e20111129215359"> <title>the title</title> <channel id="1"> <name>A name</name> <onclick></onclick> </channel> <event_site> <name/> <url/> </event_site> <start_date>Thu Mar 08 2012</start_date> <start_time>11:00 AM</start_time> <end_date>null</end_date> <end_time>null</end_time> <notes>Notes for the event</notes> </event> </my_events>

To delete an event, I have this php function.

<?php include_once("phpshared.php"); function delete_event( $nodeid ) { $nodes = new SimpleXMLElement('my_events.xml', LIBXML_NOCDATA, true); $node = $nodes->xpath("/my_events/event[@id='$nodeid']"); $node->parentNode->removeChild($node); $formatted = formatXmlString($nodes->asXML()); $file = fopen ('my_events.xml', "w"); fwrite($file, $formatted); fclose ($file); } echo delete_event(trim($_REQUEST['nodeid'])); ?>

That doesn't delete the node. Is there a different way to do this?

salathe · Accepted Answer · 2012-03-10 14:36:46Z

SimpleXML allows removal of elements via PHP's unset() keyword.

For your code snippet, simply replace

$node->parentNode->removeChild($node);

with

if ( ! empty($node)) { unset($node[0][0]); }

If the XPath query returned a matching <event> element, we instruct SimpleXML to unset() it.

Aside: here are two occurrences of [0] because:

xpath() returns an array, even if only one element matches. So [0] is used to get the first item in that array, which is the element we want to delete.
The SimpleXMLElement returned from $node[0] represents a collection of <event> elements (but if you access elements/attributes on it then the values from the first in the collection is used). So, we use [0] to get at the actual SimpleXMLElement that we want to delete, which is the first in this magical collection.

Thanks for the answer. I went with the other option because I want to be able to access the node as a DOM.
@salathe point about the second [0] index was particularly helpful and is a big gotcha.

Community · Accepted Answer · 2017-05-23 12:17:54Z

11

Use unset(): Remove a child with a specific attribute, in SimpleXML for PHP

edited May 23, 2017 at 12:17

CommunityBot

11 silver badge

answered Mar 10, 2012 at 7:20

Radek

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