XPath Syntax

XPath uses path expressions to select nodes or node sets in an XML document. Nodes are selected by following a path (path) or steps (steps).

XML Example Document

We will use this XML document in the following examples.

<?xml version="1.0" encoding="ISO-8859-1"?>
<bookstore>
<book>
  <title lang="eng">Harry Potter</title>
  <price>29.99</price>
</book>
<book>
  <title lang="eng">Learning XML</title>
  <price>39.95</price>
</book>
</bookstore>

Selecting Nodes

XPath uses path expressions to select nodes in an XML document. Nodes are selected by following a path or step.

The following lists the most useful path expressions:

Expression Description
nodename Select all child nodes of this node.
/ Select from the root node.
// From the matching selected current node, select nodes in the document without considering their position.
. Select the current node.
.. Select the parent node of the current node.
@ Select attributes.

Example

In the following table, we have listed some path expressions and their corresponding results:

Path Expression Results
bookstore Select all child nodes of the bookstore element.
/bookstore

Select the root element bookstore.

Note: If the path starts with a forward slash (/), then this path always represents an absolute path to an element!
bookstore/book Select all book elements that are children of the bookstore element.
//book Select all book child elements, regardless of their position in the document.
bookstore//book Select all book elements that are descendants of the bookstore element, regardless of their position under bookstore.
//@lang Select all attributes named lang.

Predicates (Predicates)

Predicates are used to find a specific node or a node that contains a specified value.

Predicates are enclosed in square brackets.

Example

In the following table, we list some path expressions with their corresponding results:

Path Expression Results
/bookstore/book[1] Select the first book element that is a child of the bookstore element.
/bookstore/book[last()] Select the last book element that is a child of the bookstore element.
/bookstore/book[last()-1] Select the second-to-last book element that is a child of the bookstore element.
/bookstore/book[position()<3] Select the first two book elements that are children of the bookstore element.
//title[@lang] Select all title elements that have an attribute named lang.
//title[@lang='eng'] Select all title elements that have a lang attribute with the value of eng.
/bookstore/book[price>35.00] Select all book elements within the bookstore element, and the value of the price element must be greater than 35.00.
/bookstore/book[price>35.00]/title Select all title elements of the book elements within the bookstore element, and whose price elements have a value greater than 35.00.

Select Unknown Nodes

XPath wildcards can be used to select unknown XML elements.

Wildcard Description
* Match any element node.
@* Match any attribute node.
node() Match any type of node.

Example

In the following table, we list some path expressions and the results of these expressions:

Path Expression Results
/bookstore/* Select all child elements of the bookstore element.
//* Select all elements in the document.
//title[@*] Select all title elements with attributes.

Select Multiple Paths

By using the "|" operator in path expressions, you can select multiple paths.

Example

In the following table, we list some path expressions and the results of these expressions:

Path Expression Results
//book/title | //book/price Select all title and price elements of the book element.
//title | //price Select all title and price elements in the document.
/bookstore/book/title | //price Select all title elements that belong to the book element of the bookstore element, as well as all price elements in the document.