RE: [xsl] xsl array alternatives (novice)

[Wendell Piez <wapiez at mulberrytech dot com>]

Isaac,

At 03:41 PM 9/18/2002, Stuart wrote:
> > Exhibit A. --before
> > (many other irrelevent records)...
> > <nodeA att1="True" att2="N" att3="1234"/>
> > <nodeA att1="True" att2="N" att3="321"/>
> > <nodeA att1="True" att2="N" att3="456"/>
> > <nodeA att1="True" att2="Y" att3="9876"/>
> > <nodeB att1="True" att5="Y" att3="45"/>
> > <nodeB att1="True" att5="N" att3="65"/>
> > <nodeC att1="True" att7="Y" att3="784"/>
> > <nodeC att1="True" att7="Y" att3="412"/>
> > <nodeC att1="True" att7="N" att3="635"/>
> > ...(many other irrelevent records)
> >
> > I would like to create xml output that looks something like this:
> >
> > Exhibit B. --after
> > (many irrelevent records)...
> > <nodeA att1="True" att2="N" att3="1234"/>
> > <nodeA att1="True" att2="N" att3="321"/>
> > <nodeA att1="True" att2="N" att3="456"/>
> > <nodeB att1="True" att5="N" att3="65"/>
> > <nodeC att1="True" att7="N" att3="635"/>
> > ...(many irrelevent records that may or may not have duplicate attribute
> > names and values)
> > <nodeA att1="True" att2="Y" att3="9876"/>
> > <nodeB att1="True" att5="Y" att3="45"/>
> > <nodeC att1="True" att7="Y" att3="784"/>
> > <nodeC att1="True" att7="Y" att3="412"/>
> > <end of document/>
>
> Why not use a key:
>
> <xsl:key name="getNodes" match="nodeA|nodeB|nodeC" use="@*"/>
>
> Then all you need to do is:
>
> <xsl:copy-of select="key('getNodes','N')"/>
> <xsl:copy-of select="key('getNodes','Y')"/>
This works fine, and in many cases may be the best way to approach it.

A simpler solution is just to filter the elements out with select 
attributes on apply-templates (or copy-of). This avoids the overhead of the 
key (as if that were frequently a problem: it's not):

<xsl:template match="parent-of-nodes">
  <xsl:copy-of select="*[@* = 'N']"/>
  <xsl:copy-of select="*[@* = 'Y']"/>
</xsl:template>

Like Stuart's solution, this assumes that any attribute marked as 'N' pulls 
the node into the N category, any attribute marked 'Y' pulls it into the Y 
category. It depends on the rule for equality of node sets with strings 
(they are equal if the node set -- here, the set of all an element's 
attributes -- contains any node equal to the string.) The logic can easily 
be tightened, of course.

This is a pretty basic application of XSLT; as you can see no procedural 
thinking (such as where you're going to "put" these nodes, as in an array) 
is necessary at all.

Cheers,
Wendell


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Wendell Piez                            mailto:wapiez@mulberrytech.com
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