How can I delete a child from an XML file via simplexml? - php

Question

I've got the following xml file:
<?xml version="1.0" encoding="UTF-8"?>
<root>
<number_of_gr>
3
</number_of_gr>
<group id="0">
<name>Admins</name>
<backend>1</backend>
<every_plugin_feature> 1 </every_plugin_feature>
</group>
<group id="1">
<name>Users</name>
<backend>0</backend>
<every_plugin_feature>0</every_plugin_feature>
</group>
<group id="2">
<name>Moderators</name>
<backend>0</backend>
<every_plugin_feature>0</every_plugin_feature>
</group>
</root>
For Example: I want to delete the group with the id="0". But I don't know how to delete a child with specified attribute in simplexml.
I've tried this code:
<?php
$xml = simplexml_load_file("../xml/groups.xml");
$delgroup = $xml->xpath("/root/group[#id='".$_GET['group']."'");
unset($delgroup);
$xml-> asXML("../xml/groups.xml");
?>
But it doesn't work.
After the process, I'll fill the gap with the id=1, but I can do it without help.
My question is: How to delete the specified group?

Answer 1

You are almost there, just a little tweak:
$delgroup = $xml->xpath("//group[#id='".$_GET['group']."'")[0];
unset($delgroup[0]);
see it working: http://codepad.viper-7.com/ZVXs4O
This requires PHP >= 5.4.
To see a bit of theory behind it: Remove a child with a specific attribute, in SimpleXML for PHP --> see hakre's answer.
PS: Remember to change <number_of_gr> - or delete this node from the XML, because you can always get this number by...
$groups = $xml->xpath("//group");
$numberofgroups = count($groups);