PHP access XML node element - php

Question

I am trying to edit some XML with PHP. Currently the XML looking something like:
<?xml version="1.0" encoding="utf-8"?>
<rss version="2.0">
<channel>
<title>Main Title</title>
<link>http://exmaple.com</link>
<description> blahblahblah </description>
<language>en</language>
<item>
<title>Tite1</title>
<link>http://www.example.com (THIS IS WHAT I WANT)</link>
<description>blah blah blah</description>
</item>
.
.
.
</channel>
</rss>
I've tried to access the 2nd level link but my code only changes the first Link node value. Here is the code:
$xml->load('http://www.google.com/doodles/doodles.xml');
$element = $xml->getElementsByTagName('channel')->item(0);
$secondlvl = $element->getElementsByTagName('item')->item(0);
$2ndlevellinknode = $element->getElementsByTagName('link')->item(0);
$2ndlevellinknode->nodeValue = $newvalue;
Any suggestions? Also is it possible to use this line of code in a for loop like this
for ($i = 0; $i <= 20; $i++) {
$element = $xml->getElementsByTagName('channel')->item(0);
$secondlvl = $element->getElementsByTagName('item')->item(0);
$2ndlevellinknode = $element->getElementsByTagName('link')->item($i);
$2ndlevellinknode->nodeValue = $newvalue;
}

Answer 1

this should give you an idea.
$f = simplexml_load_file('test.xml');
print $f->channel->title . "\n";
print $f->channel->link . "\n";
print $f->channel->description . "\n";
foreach($f->channel->item as $item) {
print $item->title . "\n";
}