DOMXPath

DOMXPath is a class in PHP that provides an interface to evaluate XPath expressions on a DOMDocument. XPath (XML Path Language) is a query language for selecting nodes from an XML document. The DOMXPath class allows developers to execute XPath queries on a DOMDocument object, which represents an XML or HTML document.

To use DOMXPath, you first need to create a DOMDocument object and load an XML or HTML document into it. Then, you can create a DOMXPath object, passing the DOMDocument object as a parameter. Once you have a DOMXPath object, you can use its methods to evaluate XPath expressions.

The primary method for evaluating XPath expressions is query(). This method takes an XPath expression as a string and returns a DOMNodeList containing the nodes that match the expression. The DOMNodeList can be iterated over to access the matching nodes.

DOMXPath also supports other methods for evaluating XPath expressions, such as evaluate(), which returns a single value (e.g., a string, number, or boolean) based on the expression. Additionally, you can use registerNamespace() to register XML namespaces, which can be useful when working with XML documents that use namespaces.

DOMXPath is a powerful tool for working with XML and HTML documents in PHP, allowing developers to easily query and manipulate the structure of these documents using XPath expressions. It is part of the DOM extension, which is included in PHP by default.