XML node and childnode values to array PHP

Question

I am trying to save node values to an array. This is the XML structure:

  <wildcards>
    <conference id="1">
      <seeds>
        <seed divId="1">10,7,17</seed>
        <seed divId="2">8,5,3</seed>
      </seeds>
      <wild>2,4</wild>
      <elimination>11,6,14,1,13,12,20,15</elimination>
    </conference>
 </wildcards>

The xml file can be found here
I want to associate the node values of conferences 1 with the array key being what place they are in the wildcard standings. Here is my code:

$xmlDoc = new DOMDocument(); 
$xmlDoc->load('http://www.tsn.ca/datafiles/XML/NHL/standings.xml'); 

$searchNode = $xmlDoc->getElementsByTagName('wildcards');
foreach ($searchNode as $node) {
    $conference1 = $node->getElementsByTagName('conference');
    $conference1 = $conference1->item(0)->nodeValue;
}           

echo $conference1;
//  $conference1 = str_replace(" ",",",$conference1);
$conference1Array =  explode(',', $conference1);
$conference1ArrayLength = count($conference1Array) ;

for ($i = 1; $i < $conference1ArrayLength; $i++) {
    echo $i.": ".$conference1Array[$i-1];
    echo "<br/>";
}  

If you go to this website, you can see my current output. I tried to string replace whitespace and explode on ',' to get the array correct, but it did not work.

The output of conference1 is: 10,7,17 8,5,3 2,4 11,6,14,1,13,12,20,15. Even though there is whitespace the replace did not work.

I need to have a comma after 17, 3 and 4. The idea is to insert the key for the team id into a column in my database named seed. I can then use PHP to determine what numbers are associated with each division / wildcard for table output. Here is what I mean by the association of the key and the team id / node values:

Team Id: 10 -> 1 (first in division 1)
Team Id: 7 -> 2 (second in division 1)
Team Id: 17 -> 3 (third in division 1)
Team Id: 8 -> 4 (1st in division 2)
Team Id: 5 -> 5 (2nd in division 2)
Team Id: 3 -> 6 (3rd in division 3)
Team Id: 2 -> 7 (Wildcard 1)
Team Id: 4 -> 8 (Wildcard 2)
Team Id: all the rest (eliminated)

I tried to get node values separately using code from this link, but I could not figure out how to get it to work with my situation. I don't have my attempted code for that anymore, by the way.

Edit: I have looked at the links provided and have come up with this:

$searchNode = $xmlDoc->getElementsByTagName('wildcards');
$divData = array();
foreach($searchNode as $node){
    foreach($node->childNodes as $child) {
        foreach($child->childNodes as $secondChild) {
            foreach($secondChild->childNodes as $thirdChild) {
                $divData[] = array($thirdChild->nodeName => $thirdChild->nodeValue);
            }
        }
    }
}

This is my new output

Answer 1

The output of conference1 is: 10,7,17 8,5,3 2,4 11,6,14,1,13,12,20,15. Even though there is whitespace the replace did not work.

You are almost there, use the following code to insert commas:

$conference1 = '10,7,17 8,5,3 2,4 11,6,14,1,13,12,20,15 ';
$conference1 = str_replace(" ",",",trim($conference1));

UPDATE 1

Try this to replace any characters tha are not comma or [0-9]

$new_string = preg_replace('/[^0-9,]+/u', ",", $your_string);

UPDATE 2

To fix extra commas at begin and end, do another trim $new_string = trim($your_string,",");