Proof Of The Pudding - XML

By combining the axis and node test into a location step, and combining multiple location steps into a location path, it becomes possible to locate specific nodes with the document tree quite easily. Using the following XML sample, let's consider some examples.

<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="recipe.xsl"?>
<movie 
id="67" genre="sci-fi">
<title>X-Men</title>
<!-- in case you didn't 
know, this is based on the comic - Ed -->
<cast>Hugh Jackman, Patrick Stewart 
and Ian McKellen</cast>
<director>Bryan Singer</director>
<year>2000</year>
<?play_trailer?>
</movie>

The path

/child::movie/child::cast/child::text()

references the text node

Hugh Jackman, Patrick Stewart and Ian McKellen

In order to make this a little easier to read (and write), XPath assumes a default axis of "child" if none is specified - which means that I could also write the above path as

/movie/cast/text()

Similarly, the path

/movie/comment()

references the comment string

in case you didn't know, this is based on the comic - Ed

while the path

/movie/node()[8]

references the string

Bryan Singer

The * character matches all child elements of the context node, while the @ prefix indicates that attributes, rather than elements, are to be matched. The path

/movie/*

would match all the children of the "movie" element, while the path

/movie/@*

would refer to all the attributes of the movie element. In case I need a specific attribute - say, "genre", I could use the path

/movie/@genre

or the path

/movie/attribute::genre

both of which would reference the value

sci-fi

Finally, the path

/*

would reference the first element under the document root, which also happens to be the outermost element, while the path

//*

selects all the elements in the document.

This article copyright Melonfire 2001. All rights reserved.

>>> More XML Articles          >>> More By Vikram Vaswani, (c) Melonfire

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