RE: question with using Muenchian/xsl:key (Re: sort/group/co

Thanks for the suggestion, Mike.  Yeah, it is indeed clear as mud :)
I kind of understood the find node-set intersection method: if the current
node is part of the same parent, then count(.|$set2)=count($set2).

Since my goal is to find the sum of @units for all items with the same
@itemid under the same itemlist parent, I tried:
sum(item[count(.|key('items-by-itemid',@itemid)[count(.|$this_lists_
items)=count($this_lists_items)][1])=1]/@units)
which returned me "0".

Is this the right way to find the sum of the node-set intersect?

I also tried the normal (inefficient) way of using two XPath:
<xsl:for-each select="item[not(@itemid = preceding-sibling::item/@itemid)]">
  <td class="text" width="48%"><xsl:value-of select="@itemid"/></td>
  <td class="text-right" width="6%"><xsl:value-of select="sum(item[@itemid =
current()/@itemid]/@units)"/></td>
</xsl:for-each>

That also returned me a sum of 0, is there something wrong with my
calculation of sum?

Much thanks,
Xiaocun


-----Original Message-----
From: Mike Brown
To: xsl-list@xxxxxxxxxxxxxxxx
Sent: 11/11/00 3:05 PM
Subject: Re: question with using Muenchian/xsl:key (Re: sort/group/count
probl em)

Xu, Xiaocun wrote:
>   Thanks to Jeni's suggestion, I started to apply Muenchian for
grouping.
> It works well, but I have one problem: since xsl:key is top-level
element, I
> can not seem to apply element scope with it.

This is *exactly* my problem with xsl:key. The only way to restrict your
key lookup to a certain node-set is to find the intersection of that
node-set and the result of a key lookup across the whole current node's
document.

The "Kaysian Method" of finding node-set intersections is:

	$set1[count(.|$set2)=count($set2)]

With your data, the indicated section will be $set1:
  <xsl:for-each select="item[count(. | key('items-by-itemid',
@itemid)[1]) =1]">
                                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
And you'll need to prepare a variable for $set2 right before that:
  <xsl:variable name="this_lists_items" select="item"/>

So the for-each should look like (and I haven't tested this):
  <xsl:for-each
select="item[count(.|key('items-by-itemid',@itemid)[count(.|$this_lists_
items)=count($this_lists_items)][1])=1]">

Clear as mud, eh?

   - Mike
____________________________________________________________________
Mike J. Brown, software engineer at         My XML/XSL resources:
webb.net in Denver, Colorado, USA           http://www.skew.org/xml/


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