Can someone explain this PHP+XML code to me?

[pahunrepublic]

Hi everyone!

I'm making friends with DOM+PHP+XML. I found an example in w3school tutorial but there are some things I don't understand.

<?php
$q=$_GET["q"];

$xmlDoc = new DOMDocument();
$xmlDoc->load("cd_catalog.xml");

$x=$xmlDoc->getElementsByTagName('ARTIST');

for ($i=0; $i<=$x->length-1; $i++)
{
//Process only element nodes
if ($x->item($i)->nodeType==1)
  {
  if ($x->item($i)->childNodes->item(0)->nodeValue == $q)
    {
    $y=($x->item($i)->parentNode);
    }
  }
}

$cd=($y->childNodes);

for ($i=0;$i<$cd->length;$i++)
{
//Process only element nodes
if ($cd->item($i)->nodeType==1)
  {
  echo("<b>" . $cd->item($i)->nodeName . ":</b> ");
  echo($cd->item($i)->childNodes->item(0)->nodeValue);
  echo("<br />");
  }
}
?> 

This part I understand, it's a PHP method:

$xmlDoc = new DOMDocument();
$xmlDoc->load("cd_catalog.xml");

$x=$xmlDoc->getElementsByTagName('ARTIST');

but I don't get the rest , and what is this

$x->length-1

means? What does this mean?

nodeType==1

what do the numbers represent?

Can anyone give me the URL of a good XML PHP tutorial?

 

Thank you

[jcbones]

$x->length-1 //subtract 1 from the $x->length, which is the amount of nodes in your object.

 

Node types are:

NodeType Named Constant

1 ELEMENT_NODE

2 ATTRIBUTE_NODE

3 TEXT_NODE

4 CDATA_SECTION_NODE

5 ENTITY_REFERENCE_NODE

6 ENTITY_NODE

7 PROCESSING_INSTRUCTION_NODE

8 COMMENT_NODE

9 DOCUMENT_NODE

10 DOCUMENT_TYPE_NODE

11 DOCUMENT_FRAGMENT_NODE

12 NOTATION_NODE

 

[pahunrepublic]

But why subtract 1?

[jcbones]

Because arrays start at index 0, so if the array count is 15, your highest index will be 14.