Trying to edit an XML document with a dynamic variable from PHP - php

Question

I am trying to edit an XML document using PHP, but it does not seem to work, wonder where I am going wrong!
I am trying to do it the following way which I found online. Can anyone please show me the right direction?
XML
<gold>
<coin>
<id>1</id>
<title>Gold Coin 50 Grams</title>
<price>500 rupees</price>
<dimension>20 MM</dimension>
<thumb_url>http://animsinc.com/Expertise-media.png</thumb_url>
</coin>
<coin>
<id>2</id>
<title>Gold Coin 50 Grams</title>
<price>500 rupees</price>
<dimension>20 MM</dimension>
<thumb_url>
http://animsinc.com/Expertise-media.png</thumb_url>
</coin>
...
</gold>
PHP Code
$xmlDoc = new DOMDocument();
$xmlDoc->loadXml($str);
$events = $xmlDoc->getElementsByTagName("coin");
foreach($events as $event){
$eventNames = $event->getElementsByTagName("price");
$eventN = $eventNames->item(0)->nodeValue;
if('500' == $eventN){ // ** Failed here, instead of '500',
// I used '500 rupees' and it worked, as that matches the original text.**
$eventNames->item(0)->nodeValue = $rest ;
}
}
var_dump($xmlDoc->saveXML());
Here's the desired result. Notice how I've changed the price tag to 2495 rupees.
<gold>
<coin>
<id>1</id>
<title>Gold Coin 50 Grams</title>
<price>2495 rupees</price>
<dimension>20 MM</dimension>
<thumb_url>http://animsinc.com/Expertise-media.png</thumb_url>
</coin>
<coin>
<id>2</id>
<title>Gold Coin 50 Grams</title>
<price>2495 rupees</price>
<dimension>20 MM</dimension>
<thumb_url>
http://animsinc.com/Expertise-media.png</thumb_url>
</coin>
...
</gold>

Answer 1

Here's a quick solution based on SimpleXML:
$gold = new SimpleXMLElement($xml);
foreach ($gold->coin as $coin) {
$coin->price = str_replace('500', $rest, (string) $coin->price);
}
echo $gold->asXML();
Working demo.

Answer 2

Oh hey, it was a mistake on my part, the function works perfect, instead of
if('500' == $eventN)
The Correct woulld be
if('500 rupees' == $eventN)
Dumb