Re: [xsl] Finding element with min value in multiple files

Subject: Re: [xsl] Finding element with min value in multiple files
From: Jeni Tennison <mail@xxxxxxxxxxxxxxxx>
Date: Fri, 12 Jan 2001 09:39:30 +0000
Hi Peter,

> How do I find max or min value of a given element in multiple files?

Lots of ways. A quick and simple way to find the minimum would be to
have a variable hold the values:

<xsl:variable name="costs"
              select="document(Replies/File)/Document/Cost" />

And then to find those nodes in the $costs node set where there's no
other node in the node set with a smaller value:

$costs[not($costs &lt; .)]

Another way is to use a sort in ascending order and then pick the
first in the list:

<xsl:for-each select="$costs">
   <xsl:sort select="." data-type="number" />
   <xsl:if test="position() = 1">
      <xsl:value-of select="." />
   </xsl:if>
</xsl:for-each>

A final way involves constructing a new result tree fragment holding
the costs:

<xsl:variable name="costs">
   <xsl:copy-of select="document(Replies/File)/Document/Cost" />
</xsl:variable>

and then to use this as the basis of a recursive solution.  Apply
templates to the first Cost in this list:

   <xsl:apply-templates select="$costs/Cost[1]" />

and have a template:

<xsl:template match="Cost" mode="minimum">
   <xsl:variable name="next"
                 select="following-sibling::Cost[. &lt; current()]" />
   <xsl:choose>
      <xsl:when test="$next">
         <xsl:apply-templates select="$next" mode="minimum" />
      </xsl:when>
      <xsl:otherwise>
         <xsl:value-of select="." />
      </xsl:otherwise>
   </xsl:choose>
</xsl:template>

This solution works best under XSLT 1.1, but you can use it now if you
use the node-set() extension function provided under most XSLT
processors.  For now you need to apply templates with something like:

   <xsl:apply-templates select="saxon:node-set($costs)/Cost[1]" />

Which one of the above works best will depend on how many Costs you
have, what your processor optimises and so on - try them to see.

I hope that helps,

Jeni

---
Jeni Tennison
http://www.jenitennison.com/



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