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Re: How do you get the most recent element?

Subject: Re: How do you get the most recent element?
From: David Carlisle <davidc@xxxxxxxxx>
Date: Fri, 9 Feb 2001 18:08:41 GMT
most recent element

> I'm concerned that the match will go through all the sorted notes even
> though I only want the most recent. 

If you do it that way it probably will (although it probably doesn't
matter much since you've looked at them all to sort anyway in this case)

but an alternatative to


<xsl:template match="note">
  <xsl:if test="position()=1">
    <xsl:value-of select="text"/>
  </xsl:if>
</xsl:template>


is


<xsl:template match="note"/>
<xsl:template match="note[1]">
    <xsl:value-of select="text"/>
</xsl:template>

which might be a bit easier for an optimiser to spot that the normal
case is a no-op.

If you weren't sorting and just wanted the first node in the list you
could also have gone

  <xsl:apply-templates select="note[1]">

which might be preferable to both of the above in the unsorted case.

For large data sets it may be better to use a recursive template to
find the minimum entry in O(n) time rather than use xsl:sort which is
likely to be O(n log n) (depending on how well your processor treats
recursive calls, see an earlier long thread on this)

David

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


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