DOMXPath - Select only a few items - domxpath

Question

Let's say we have this html and the following DOMXPath code:
<div>
<div>
<p>1</p>
</div>
<div>
<p>2</p>
</div>
<div>
<p>3</p>
</div>
<div>
<p>4</p>
</div>
<div>
<p>5</p>
</div>
<div>
<p>6</p>
</div>
</div>
$doc = new DOMDocument();
$doc->loadHtml($strhtml);
$doc->preserveWhiteSpace = false;
$xpath = new DOMXPath( $doc );
$nodelist = $xpath->query('//div/div[2]/p');
foreach( $nodelist as $node ) {
$result = $node->nodeValue."\n";
}
echo $result;
Obviously, $result = '2', since we asked for the value of 'p' from the second 'div' node.
Now, how can I get the values for, say, from 'div[2]' to 'div[4]' and sum them?
To be precise, I would like to know how to get "from # to #" and also how to get "this #, that #, also # and #". So two questions, for two different problems.
Thanks in advance.

Answer 1

You are able to select range of elements with DOMXPath:
as for the first problem to get "from # to #" use the
following approach:
// select nodes within specified range of positions
$nodelist = $xpath->query('//div/div[position()>1 and position()<5]');
as for the second problem to get "this #, that #, also # and #"
try the following (with | union operator):
// extracts the 2nd, 4th and 6th elements respectively
$nodelist = $xpath->query('//div/div[2] | //div/div[4] | //div/div[6]);