December 2002
Intermediate to advanced
576 pages
32h
English
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XPath
XPath is a recommendation of the World Wide Web Consortium (W3C) for locating nodes in an XML document tree. XPath is not designed to be used alone but in conjunction with other tools, such as XSLT or XPointer. These tools use XPath intensively and extend it for their own needs through new functions and new basic types.
XPath provides a syntax for locating a node in an XML document. It
takes its inspiration from the syntax used to denote paths in
filesystems such as Unix. This node, often called the
context node, depends on the context of the
XPath expression. For example, the context of an XSLT expression
found in an <xsl:template match="para">
template will be the selected <para> element
(recall that XSLT templates use XPath expressions). This node can be
compared to a Unix shell’s current directory.
Given our earlier XML examples, it is possible to write the following expressions:
-
chapter Selects the
<chapter>element descendants of the context node-
chapter/para Selects the
<para>element descendants of the<chapter>element children of the context node-
../chapter Selects the
<chapter>element descendants of the parent of the context node-
./chapter Selects the
<chapter>element descendants of the context node-
* Selects all element children of the context node
-
*/para Selects the
<para>grandchildren of the context node-
.//para Selects the
<para>element descendants (children, children of children, etc.) of the context node-
/para Selects the
<para>element children ...
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.