Question

I’ve basically got an XML file full of product information for use in an ecommerce system. I’ve been creating a script that converts these XML files into a .CSV with the data structured in a format the ecommerce system can handle (So I don’t need to copy/paste columns over every time the vendor provides new XML files). The category of each product is defined like this:

<web_category1>3</web_category1>
<web_category2>1</web_category2>
<web_category3>6</web_category3>

web_category3 being the category of the item and 1 and 2 being the parent categories of the product’s category. The thing is that some items are nested under 2 categories..or sometimes 5. So I need to figure out a way for PHP to grab the web_category with the highest number after it since that’s always going to be the product’s category.

Thanks!

Answer 1

@ben’s answer is correct, but is a little intense for me. SimpleXMLElement objects are nice because you can easily cast them to an array. So, a simpler solution would be to cast it to an array and use max to determine the highest value in the resulting array:

$str = '
<item>
    <web_category1>3</web_category1>
    <web_category2>1</web_category2>
    <web_category3>6</web_category3>
</item>
';

$xml = new SimpleXMLElement($str);
echo max((array)$xml); // outputs: 6

UPDATE

Based on your comment below, let’s assume you need to get the max of all the <item> elements that occur in an XML file and not just one (like above). To handle this you could use SimpleXMLElement::xpath^docs to get an array of all the occurrences of <item> then execute the same casting trick inside a loop over the xpath result:

$str = '
<xml>
  <product1>
    <item>
      <web_category1>3</web_category1>
      <web_category2>1</web_category2>
      <web_category3>6</web_category3>
    </item>
  </product1>
  <product2>
    <item>
      <web_category4>17</web_category4>
      <web_category5>0</web_category5>
    </item>
  </product2>
</xml>
';

$xml = new SimpleXMLElement($str);

$allItems = array();
$items = $xml->xpath('//item');
foreach($items as $item) {
  $allItems = array_merge($allItems, (array)$item);
}
echo max($allItems); // outputs: 17

UPDATE 2

Okay, last time. If this isn’t exactly what you’re trying to do, you should at least have enough examples to figure it out from here. Consider:

$str = '
<xml>
  <product1>
    <web_category1>3</web_category1>
    <web_category2>1</web_category2>
    <web_category3>6</web_category3>
  </product1>
  <product2>
    <web_category4>17</web_category4>
    <web_category5>0</web_category5>
  </product2>
  <product3>
    <web_category6>17</web_category6>
    <web_category7>21</web_category7>
  </product3>
</xml>
';

$xml = new SimpleXMLElement($str);

// assumes that product node names start with "product"
$products = $xml->xpath("//*[starts-with(name(),'product')]");
foreach ($products as $p) {
  $catNames = array_keys((array)$p);
  $catNums  = preg_replace("/[^\d]/", "", $catNames);
  echo $p->getName() . ' - highest category: ' . max($catNums) . "\n";
}

The above code outputs the following:

product1 - highest category: 3
product2 - highest category: 5
product3 - highest category: 7