XPath - XPath Introduction XPath is a language for finding...

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1 XPath Introduction XPath is a language for finding information in an XML document. What You Should Already Know Before you continue you should have a basic understanding of the following: HTML / XHTML XML / XML Namespaces If you want to study these subjects first, find the tutorials on our Home page . What is XPath? XPath is a syntax for defining parts of an XML document XPath uses path expressions to navigate in XML documents XPath contains a library of standard functions XPath is a major element in XSLT XPath is a W3C recommendation XPath Path Expressions XPath uses path expressions to select nodes or node-sets in an XML document. These path expressions look very much like the expressions you see when you work with a traditional computer file system. XPath Standard Functions XPath includes over 100 built-in functions. There are functions for string values, numeric values, date and time comparison, node and QName manipulation, sequence manipulation, Boolean values, and more. XPath is Used in XSLT
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2 XPath is a major element in the XSLT standard. Without XPath knowledge you will not be able to create XSLT documents. You can read more about XSLT in our XSLT tutorial . XQuery and XPointer are both built on XPath expressions. XQuery 1.0 and XPath 2.0 share the same data model and support the same functions and operators. You can read more about XQuery in our XQuery tutorial . XPATH is a W3C Recommendation XPath became a W3C Recommendation 16. November 1999. XPath was designed to be used by XSLT, XPointer and other XML parsing software. To read more about the XPATH activities at W3C, please read our W3C tutorial .
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3 XPath Nodes XPath Terminology Nodes In XPath, there are seven kinds of nodes: element, attribute, text, namespace, processing- instruction, comment, and document nodes. XML documents are treated as trees of nodes. The topmost element of the tree is called the root element. Look at the following XML document: <?xml version="1.0" encoding="ISO-8859-1"?> <bookstore> <book> <title lang="en">Harry Potter</title> <author>J K. Rowling</author> <year>2005</year> <price>29.99</price> </book> </bookstore> Example of nodes in the XML document above: <bookstore> (root element node) <author>J K. Rowling</author> (element node) lang="en" (attribute node) Atomic values Atomic values are nodes with no children or parent. Example of atomic values: J K. Rowling
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4 "en" Items Items are atomic values or nodes. Relationship of Nodes Parent Each element and attribute has one parent. In the following example; the book element is the parent of the title, author, year, and price: <book> <title>Harry Potter</title> <author>J K. Rowling</author> <year>2005</year> <price>29.99</price> </book> Children Element nodes may have zero, one or more children. In the following example; the title, author, year, and price elements are all children of the
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XPath - XPath Introduction XPath is a language for finding...

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