PHP XML数组切片和反向或反向然后数组切片

Have an xml file ... the webpage shows the most recent 50 new nodes. When you click a link 'show more' it adds a ?node= to the url which I $_get to change the slice starting point ($start_node) ... but it doesn't. The value DOES change but the slice doesn't work. Por que?!

$master = array_slice($xml_get->xpath('unit'), $start_node);
$master = array_reverse($master);

$i = 0;

foreach ($master as $arc) {

    $last_data = $arc[0]->data;
    $last_link = $arc[0]->link;

    // doing stuff with values

    $i++;
    if ($i >= 50) {
        break;
    }
}

If you don't use the third parameter of array_slice() which is the number of elements to extract, you will retrieve all entries from the start node on. When you reverse this and extract the first 50, this will always be the last 50 of all of the nodes.

So to extract from $start_node to $start_node+50...

$master = array_slice($xml_get->xpath('unit'), $start_node, 50);
$master = array_reverse($master);
foreach($master as $arc) {
    $last_data  = $arc[0]->data;
    $last_link  = $arc[0]->link;

    // doing stuff with values
}