[xsl] Re: building a hierarchical classification out of flat and redundant data

["mnews-xsl@xxxxxx" <mnews-xsl@xxxxxx>]

Hello,

the following uses a recursive template and tracks upward / downward pointers
with keys. It also works with more than one single root node.

Regards


<?xml version="1.0" encoding="iso-8859-1"?>

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

<xsl:output method="xml" indent="yes"/>

<xsl:key name="ptr-up" match="document" use="*[last()-1]"/>
<xsl:key name="ptr-down" match="document" use="*[last()-3]"/>

<xsl:template match="/documents">
	<nodes>
		<xsl:apply-templates select="document[not(key('ptr-up', *[last()-3]))]"/>
	</nodes>
</xsl:template>

<xsl:template match="document">
	<node id="{*[last()-1]}" name="{*[last()]}">
		<xsl:apply-templates select="key('ptr-down', *[last()-1])"/>
	</node>
</xsl:template>

</xsl:stylesheet>

> On 7/24/06, Georg Hohmann <georg.hohmann@xxxxxxxxx> wrote:
> > Dear XSLT-Community,
> >
> > i have problem with some "strange" type of data which i have to
> > convert to a hierarchical xml structure.
> >
> > My source is a huge xml file which represents a decimal
> > classifikation. It contains so called documents, where each document
> > represents one node of the classification. Furthermore each documents
> > shows the direct parents of a node. It's a structure like this
> > (example taken from http://www.udcc.org):
> > ...
> > <document>
> >        <tag1>3</tag1>
> >        <tag1a>Social Sciences</tag1a>
> > </document>
> > <document>
> >        <tag1>3</tag1>
> >        <tag1a>Social Sciences</tag1a>
> >        <tag2>32</tag2>
> >        <tag2a>Politics</tag2a>
> > </document>
> > <document>
> >        <tag1>3</tag1>
> >        <tag1a>Social Sciences</tag1a>
> >        <tag2>32</tag2>
> >        <tag2a>Politics</tag2a>
> >        <tag3>326</tag3>
> >        <tag3a>Slavery</tag3a>
> > </document>
> > ...
> > As you can see there is no hierarchical information in it instead of
> > the names and the sequence of the tags. In my real data i have up to 9
> > levels, but not every time. My result should look like this (or
> > something similar):
> > ...
> > <node id="3" name="Social Science">
> >   <node id="32" name="Politics">
> >      <node id="326" name="Slavery"/>
> >   </node>
> > </node>
> > ...
> > I have simply no idea what to start with to archive this result. I
> > guess the first step would be to get rid of all those redundant
> > content, but i don't know how. And i even can't figure out how to
> > build the hierachichal structure the same time.
> >
> > Has anyone a good starting point for this?