XPath is a language for addressing specific parts of a document. XPath models an XML document
as a tree of nodes. An XPath expression is a mechanism for navigating through and selecting
nodes from the document. An XPath expression is, in a way, analogous to an SQL query used to
select records from a database.
Note: If an XPath expression is run over a JSON document, it is
converted to XML and the XPath is executed over the converted XML document.
There are various types of nodes, including element nodes, attribute nodes, and text nodes.
XPath defines a way to compute a string-value for each type of node.
XPath defines a library of standard functions for working with strings, numbers and boolean
expressions.
Examples:
- child::* - Selects all children of the root node.
- .//name - Selects all
<name> elements
and descendants of the current node.
- /catalog/cd[price>10.80] - Selects all the
<cd> elements that have a <price> element
with a value larger than 10.80.
- //prolog - Finds all
<prolog>
elements.
- //prolog[@platform='mac'] - Finds all
<prolog> elements that have the @platform
attribute value set to mac.
- //child::prolog - Selects all
@prolog
elements and the child content.
- /*[count(//accountNumber) > 5] - Searches for instances where
more than 5
<accountNumber> elements are found.
- collection('file:/C:/path/to/folder/?select=*.xml')/*[not(//prolog)] - Finds a
list of all XML files that do not contain any
<prolog>
elements.
To find out more about XPath, see http://www.w3.org/TR/xpath.