How to find element in already parsed HTML data - php

Question

Here I have a very simple code to grab all the 'div' elements with the classname 'info_block'. I am wondering how would I go about finding another element with the classname 'price' from within 'info_block' and display it instead of the whole 'info_block' element.
Main Goal: Find the price in each element with classname 'info_block'. but do inside the foreach, because I may need to find other elements.
<?php
$page = file_get_contents('example.com');
$dom = new DOMDocument();
$dom->loadHTML($page);
$xpath = new DOMXPath($dom);
$div1 = $xpath->query('//div[#class="info_block"]');
foreach ($div1 as $var1){
//echo $dom->saveHTML($var1);
}
?>
There is a element in each of the 'info_block' with a classname 'price' and I would like to display only that element. Like so...
foreach ($div1 as $var1){
$dom2 = new DOMDocument();
$dom2->loadHTML($dom->saveHTML($var1));
$xpath2 = new DOMXPath($dom2);
$div2 = $xpath2->query('//div[#class="price"]');
$div2 = $div2->item(0);
echo $dom2->saveHTML($div2);
}
But instead of just giving me the price it returns the whole HTML for 'info_block' as it did before.

Answer 1

You could provide each <div class="info_block"> found and search for <div class="price">" by providing it in the second argument of ->query():
$div1 = $xpath->query('//div[#class="info_block"]');
foreach ($div1 as $var1){
$div2 = $xpath->query('./div[#class="price"]', $var1);
// ^ each div
$div2 = $div2->item(0);
echo $dom->saveHTML($div2);
}
Note: You do not need to create another instance of DOM and DOMXpath.
This example is taken into context of this kind of HTML semantic:
<div class="info_block"> // each info block
<div class="price">1</div> // inside of it has price
</div>
<div class="info_block">
<div class="price">2</div>
</div>

Answer 2

You can combine queries in XPath to find all the desired elements in one go
$xpath->query('//div[#class="info_block"]|//div[#class="price"]');

Answer 3

You can specify dom elements for doing relative XPath queries. Its optional in xpath->query method
<?php
$page = file_get_contents('example.com');
$dom = new DOMDocument();
$dom->loadHTML($page);
$xpath = new DOMXPath($dom);
$div1 = $xpath->query('//div[#class="info_block"]');
foreach ($div1 as $var1){
$div2 = $xpath2->query('//a[#class="price"]', $var1);
foreach ($div2 as $var2) {
echo $var2->nodeValue. "\n";
}
}
?>
For more you can see xpath documentation here
xpath query documentation