Re: [xsl] XPath question

[Evan Lenz <evan@xxxxxxxxxxxx>]

This is an example of the classic grouping problem.

Here's an XSLT 1.0 solution:

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

  <xsl:output indent="yes"/>

  <xsl:template match="data">
    <data>
      <series>
        <xsl:for-each 
select="series/event[not(@time=preceding::event/@time)]">
          <record time="{@time}">
            <xsl:for-each 
select="//data/series/event[@time=current()/@time]">
              <sample ID="{../@ID}">
                <xsl:value-of select="."/>
              </sample>
            </xsl:for-each>
          </record>
        </xsl:for-each>
      </series>
    </data>
  </xsl:template>

  <xsl:template match="@*|*">
    <xsl:copy>
      <xsl:apply-templates select="@*|*"/>
    </xsl:copy>
  </xsl:template>

</xsl:stylesheet>


Here's an XSLT 2.0 solution (tested on Saxon 7.1):

<xsl:stylesheet version="2.0" 
xmlns:xsl="http://www.w3.org/1999/XSL/Transform";>

  <xsl:output indent="yes"/>

  <xsl:template match="data">
    <data>
      <series>
        <xsl:for-each-group select="series/event" group-by="@time">
          <record time="{@time}">
            <xsl:for-each select="current-group()">
              <sample ID="{../@ID}">
                <xsl:value-of select="."/>
              </sample>
            </xsl:for-each>
          </record>
        </xsl:for-each-group>
      </series>
    </data>
  </xsl:template>

  <xsl:template match="@*|*">
    <xsl:copy>
      <xsl:apply-templates select="@*|*"/>
    </xsl:copy>
  </xsl:template>

</xsl:stylesheet>

For an explanation of this new XSLT 2.0 feature (as well as a few others), 
see the second page of my article[1] on XML.com.

Hope this helps,
Evan

[1] http://www.xml.com/pub/a/2002/04/10/xslt2.html?page=2


On Thursday, May 2, 2002, at 07:45  PM, Joseph Brightly wrote:

> I'm trying to perform an xml->xml transform and I can't seem
> to be able to make it work. The following is the xml, with
> extraneous stuff taken out.
>
> I need to go from this:
>
> <session startDate="03/23/2002" startTime="11:20:05">
> <data>
>     <series ID="100">
>         <event time="11:20:05">65.05</event>
>         <event time="11:21:05">65.23</event>
>         <event time="11:22:05">67.46</event>
>     </series>
>     <series ID="200">
>         <event time="11:20:05">40.15</event>
>         <event time="11:21:05">40.17</event>
>         <event time="11:22:05">40.56</event>
>     </series>
>
>     1 - N of these <series> elements...
>
> </data>
> </Session>
>
> To this:
>
> <session startDate="03/23/2002" startTime="11:20:05">
> <data>
> <series>
>     <record time="11:20:05">
>         <sample ID="100">65.05</sample>
>         <sample ID="200">40.15</sample>
>     </record>
>     <record time="11:21:05">
>         <sample ID="100">65.23</sample>
>         <sample ID="200">40.17</sample>
>     </record>
>     <record time="11:22:05">
>         <sample ID="100">67.46</sample>
>         <sample ID="200">40.56</sample>
>     </record>
>
>     Etc...
>
> </series>
> </data>
> </session>
>
> This is something like a table join in sql, and I can't find a way
> to accomplish it.
>
> Any help would be greatly appreciated.
>
>
>  XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list


XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list