work

This topic reviews the syntax examples that appear throughout the XPath Reference. All are based on the Sample XML File for XPath Syntax (inventory.xml). For an example of using an XPath expression in a test file, see "Example of Unions ( | )", at the bottom of this topic.

Expression	Refers to
`./author`	All `<author>` elements within the current context. Note that this is equivalent to the expression in the next row.
`author`	All `<author>` elements within the current context.
`first.name`	All `<first.name>` elements within the current context.
`/bookstore`	The document element (`<bookstore>`) of this document.
`//author`	All `<author>` elements in the document.
`book[/bookstore/@specialty=@style]`	All `<book>` elements whose `style` attribute value is equal to the `specialty` attribute value of the `<bookstore>` element at the root of the document.
`author/first-name`	All `<first-name>` elements that are children of an `<author>` element.
`bookstore//title`	All `<title>` elements one or more levels deep in the `<bookstore>` element (arbitrary descendants). Note that this is different from the expression in the next row.
`bookstore/*/title`	All `<title>` elements that are grandchildren of `<bookstore>` elements.
`bookstore//book/excerpt//emph`	All `<emph>` elements anywhere inside `<excerpt>` children of `<book>` elements, anywhere inside the `<bookstore>` element.
`.//title`	All `<title>` elements one or more levels deep in the current context. Note that this situation is essentially the only one in which the period notation is required.
`author/*`	All elements that are the children of `<author>` elements.
`book/*/last-name`	All `<last-name>` elements that are grandchildren of `<book>` elements.
`/`	All grandchildren elements of the current context.
`*[@specialty]`	All elements with the `specialty` attribute.
`@style`	The `style` attribute of the current context.
`price/@exchange`	The `exchange` attribute on `<price>` elements within the current context.
`price/@exchange/total`	Returns an empty node set, because attributes do not contain element children. This expression is allowed by the XML Path Language (XPath) grammar, but is not strictly valid.
`book[@style]`	All `<book>` elements with `style` attributes, of the current context.
`book/@style`	The `style` attribute for all `<book>` elements of the current context.
`@*`	All attributes of the current element context.
`./first-name`	All `<first-name>` elements in the current context node. Note that this is equivalent to the expression in the next row.
`first-name`	All `<first-name>` elements in the current context node.
`author[1]`	The first `<author>` element in the current context node.
`author[first-name][3]`	The third `<author>` element that has a `<first-name>` child.
`my:book`	The `<book>` element from the `my` namespace.
`my:*`	All elements from the `my` namespace.
`@my:*`	All attributes from the `my` namespace (this does not include unqualified attributes on elements from the `my` namespace).

Note that indexes are relative to the parent. Consider the following data:

Copy Code

<x>
  <y/>
  <y/>
</x>
<x>
  <y/>
  <y/>
</x>

Expression	Refers to
`x/y[1]`	The first `<y>` child of each `<x>`. This is equivalent to the expression in the next row.
`x/y[position() = 1]`	The first `<y>` child of each `<x>`.
`(x/y)[1]`	The first `<y>` from the entire set of `<y>` children of `<x>` elements.
`x[1]/y[2]`	The second `<y>` child of the first `<x>`.

The remaining examples refer to the Sample XML file for XPath.

Expression	Refers to
`book[last()]`	The last `<book>` element of the current context node.
`book/author[last()]`	The last `<author>` child of each `<book>` element of the current context node.
`(book/author)[last()]`	The last `<author>` element from the entire set of `<author>` children of `<book>` elements of the current context node.
`book[excerpt]`	All `<book>` elements that contain at least one `<excerpt>` element child.
`book[excerpt]/title`	All `<title>` elements that are children of `<book>` elements that also contain at least one `<excerpt>` element child.
`book[excerpt]/author[degree]`	All `<author>` elements that contain at least one `<degree>` element child, and that are children of `<book>` elements that also contain at least one `<excerpt>` element.
`book[author/degree]`	All `<book>` elements that contain `<author>` children that in turn contain at least one `<degree>` child.
`author[degree][award]`	All `<author>` elements that contain at least one `<degree>` element child and at least one `<award>` element child.
`author[degree and award]`	All `<author>` elements that contain at least one `<degree>` element child and at least one `<award>` element child.
`author[(degree or award) and publication]`	All `<author>` elements that contain at least one `<degree>` or `<award>` and at least one `<publication>` as the children
`author[degree and not(publication)]`	All `<author>` elements that contain at least one `<degree>` element child and that contain no `<publication>` element children.
`author[not(degree or award) and publication]`	All `<author>` elements that contain at least one `<publication>` element child and contain neither `<degree>` nor `<award>` element children.
`author[last-name = "Bob"]`	All `<author>` elements that contain at least one `<last-name>` element child with the value `Bob`.
`author[last-name[1] = "Bob"]`	All `<author>` elements where the first `<last-name>` child element has the value `Bob`. Note that this is equivalent to the expression in the next row.
`author[last-name [position()=1]= "Bob"]`	All `<author>` elements where the first `<last-name>` child element has the value `Bob`.
`degree[@from != "Harvard"]`	All `<degree>` elements where the `from` attribute is not equal to `"Harvard"`.
`author[. = "Matthew Bob"]`	All `<author>` elements whose value is `Matthew Bob`.
`author[last-name = "Bob" and ../price > 50]`	All `<author>` elements that contain a `<last-name>` child element whose value is `Bob`, and a `<price>` sibling element whose value is greater than 50.
`book[position() <= 3]`	The first three books (1, 2, 3).
`author[not(last-name = "Bob")]`	All `<author>` elements that do no contain `<last-name>` child elements with the value `Bob`.
`author[first-name = "Bob"]`	All `<author>` elements that have at least one `<first-name>` child with the value `Bob`.
`author[* = "Bob"]`	all author elements containing any child element whose value is `Bob`.
`author[last-name = "Bob" and first-name = "Joe"]`	All `<author>` elements that has a `<last-name>` child element with the value `Bob` and a `<first-name>` child element with the value `Joe`.
`price[@intl = "Canada"]`	All `<price>` elements in the context node which have an `intl` attribute equal to `"Canada"`.
`degree[position() < 3]`	The first two `<degree>` elements that are children of the context node.
`p/text()[2]`	The second text node in each `<p>` element in the context node.
`ancestor::book[1]`	The nearest `<book>` ancestor of the context node.
`ancestor::book[author][1]`	The nearest `<book>` ancestor of the context node and this `<book>` element has an `<author>` element as its child.
`ancestor::author[parent::book][1]`	The nearest `<author>` ancestor in the current context and this `<author>` element is a child of a `<book>` element.

Example of Unions ( | )

To demonstrate the union operation, we use the following XPath expression:

x | y/x

selects all the <x> elements whose values are green or blue in the following XML file:

XML File (data1.xml)

Xml

Copy Code

<?xml version='1.0'?>
<?xml-stylesheet type="text/xsl" href="union.xsl"?>
<root>
   <x>green</x>
   <y>
      <x>blue</x>
      <x>blue</x>
   </y>
   <z>
      <x>red</x>
      <x>red</x>
   </z>
   <x>green</x>
</root>

XSLT File (union.xsl)

Xml

Copy Code

<?xml version='1.0'?>
<xsl:stylesheet version="1.0"
      xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

<xsl:template match="root">
   <xsl:for-each select="x | y/x">
      <xsl:value-of select="."/>,
      <xsl:if test="not(position()=last())">,</xsl:if>
   </xsl:for-each>
</xsl:template>

</xsl:stylesheet>

Formatted Output

green,blue,blue,green

Processor Output

<?xml version="1.0" encoding="UTF-16"?>green,blue,blue,green

Reference

Location Path Examples

Concepts

Sample XML File for XPath Syntax (inventory.xml)