SimpleXML: Selecting Elements Which Have A Certain Attribute Value

Question

In an XML document, I have elements which share the same name, but the value of an attribute defines what type of data it is, and I want to select all of those elements whic

Answer 1

I just made a function to do this for me; it only grabs the first result though. Your mileage may vary.

function query_attribute($xmlNode, $attr_name, $attr_value) {
  foreach($xmlNode as $node) { 
    if($node[$attr_name] == $attr_value) {
        return $node;
    }
  }
}

Usage:

echo query_attribute($MySimpleXmlNode->Customer, "type", "human")->Name;

(For the XML below)

<Root><Customer type="human"><Name>Sam Jones</name></Customer></Root>

Answer 2

Try this XPath:

/object/data[@type="me"]

Which reads as:

• Select (/) children of the current element called object
• Select (/) their children called data
• Filter ([...]) that list to elements where ...
  • the attribute type (the @ means "attribute")
  • has the text value me

So:

$myDataObjects = $simplexml->xpath('/object/data[@type="me"]');

If object is not the root of your document, you might want to use //object/data[@type="me"] instead. The // means "find all descendents" rather than "find all children".