RE: [xsl] Sorting and grouping

Subject: RE: [xsl] Sorting and grouping
From: "Michael Kay" <michael.h.kay@xxxxxxxxxxxx>
Date: Wed, 2 Oct 2002 11:24:28 +0100
> I have a non-sorted list I want to sort, but I also want to 
> know when a group is new.

Try not to think so procedurally: you're not interested in when things
happen, only in how the output is functionally related to the input.

Generally with sorting-then-grouping problems I advise a two-phase
transformation, using a temporary tree (result tree fragment) as the
intermediate result. This needs the xx:node-set() extension to access
this tree in the second phase.

Michael Kay
Software AG
home: Michael.H.Kay@xxxxxxxxxxxx
work: Michael.Kay@xxxxxxxxxxxxxx 



  I've managed to do this using 
> for-each, sort and an if with a "not preceding".  (Thanks to 
> the faq and posts in this list)
> 
> But the "not preceding" is not looking at the sorted order - 
> it's looking at the orginal order in the XML-file.  I want it 
> to "search" the sorted list.
> 
> Example:
> 
> XSL:
> <xsl:output method="html" />
> 
> <xsl:template match="check">
> <html>
> <table border="1">
> <tr><th>new</th><th>i</th><th>g</th></tr>
> <xsl:for-each select="news"><xsl:sort select="@i" 
> order="descending"/> <tr> <td><xsl:if 
> test="not(preceding::g=g)">*</xsl:if></td>
> <td><xsl:value-of select="@i"/></td>
> <td><xsl:value-of select="g"/></td>
> </tr>
> </xsl:for-each>
> 
> </table>
> </html>
> </xsl:template>
> 
> </xsl:stylesheet>
> 
> XML:
> <check>
> <news i="6"><g>3</g></news>
> <news i="1"><g>2</g></news>
> <news i="5"><g>2</g></news>
> <news i="4"><g>1</g></news>
> <news i="3"><g>1</g></news>
> <news i="2"><g>3</g></news>
> </check>
> 
> This outputs : (n = new, i=item, g=group)
> n i g 
> * 6 3 
>   5 2 
> * 4 1 
>   3 1 
>   2 3 
> * 1 2        <- i=1 is the first use of group 2 in the XML
> 
> 
> But I want it to output :
> 
> n i g 
> * 6 3 
> * 5 2        <- i=5 is the first use of group 2 in the sorted list
> * 4 1 
>   3 1 
>   2 3 
>   1 2 
> 
> 
> Thanks in advance for any help!
> 
> Regards
> Martin Gundersen
> martin@xxxxxxxxxxxxx
> Oslo, Norway
> 
>  XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list
> 


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