PHP search and read node data in XML file

It seemed like a simple thing, but it took hours and heartbroken. In the file below, find a url with id=6. The file name is my.xml.

<?xml version="1.0" encoding="UTF-8" ?>
<urlfile>
	<urls>
	  <id>0</id>
	  <url>http://www.000.com</url>	
	</urls>
	<urls>
	  <id>1</id>
	  <url>http://www.1111.com</url>	
	</urls>
	<urls>
	  <id>4</id>
	  <url>http://www.44444.com</url>	
	</urls>
	<urls>
	  <id>6</id>
	  <url>http://www.66666.com</url>	
	</urls>
</urlfile>

Do that in an action in a Zend Framework controller. The code snippet is as follows:

$file = file_get_contents('my.xml');
$xml = simplexml_load_string($file);
$result = $xml->xpath('/urlfile/urls');
require_once('Zend/Debug.php');
Zend_Debug::Dump($result);

As a result, at the level of the urls node, it becomes a normal array. The next layer is still the SimpleXMLElement object. The data from the dump is as follows:

array(4) {
  [0] => object(SimpleXMLElement)#41 (2) {
    ["id"] => string(1) "0"
    ["url"] => string(18) "http://www.000.com"
  }
  [1] => object(SimpleXMLElement)#42 (2) {
    ["id"] => string(1) "1"
    ["url"] => string(41) "http://www.1111.com"
  }
  [2] => object(SimpleXMLElement)#43 (2) {
    ["id"] => string(1) "4"
    ["url"] => string(33) "http://www.4444.com"
  }
  [3] => object(SimpleXMLElement)#44 (2) {
    ["id"] => string(1) "6"
    ["url"] => string(33) "http://www.6666.com"
  }
}

Is there a difference? have! If it is a normal array, you will definitely find the corresponding url when id=6.

foreach ($result as $k => $list )
{
	if($list['id'] == $id ) 
    {
       $row['url'] = $list['url']; 
       //$row是我要送到页的一个数组，里面还有其它很多数据
    }
}

As a result you found,

$row['url'] = null

The correct way is:

foreach ($result as $k => $list )
{
	if($list->id == $id ) 
    {
       $row['url'] = $list->url; 
       //$row是我要送到页的一个数组，里面还有其它很多数据
    }
}

is $list->id instead of $list['id']. is $list->url, not $list['url'].