At 2012-10-08 20:32 -0400, Birnbaum, David J wrote:
Dear XSLT list,
Is there an easy way in XPath (not using XSLT instructions) to
select only the first occurrence of a specific value in a sequence
of atomic values, so as to return the sequence in the original
order, but with re-occurrences of each value after the first
appearance of that value removed? For example, given an input sequence:
('Matthew','Mark','Luke','Matthew','John')
I want to produce
('Matthew','Mark','Luke','John')
I can't rely on using distinct-values() because that isn't
guaranteed to keep specifically the *first* occurrence of a value.
In an XSLT context I can construct a temporary tree, poke each value
into an element, all on the same level in the hierarchy, and then test for:
*[not(preceding-sibling::* = .)]
but I don't know how to write an XPath predicate that will filter
the sequence of *atomic values* the way I want. Is this just a blind
spot? Can anyone advise?
If I'm allowed to put the sequence into a variable, then:
T:\ftemp>xslt2 david.xsl david.xsl
<?xml version="1.0" encoding="UTF-8"?>Matthew Mark Luke John
T:\ftemp>type david.xsl
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
version="2.0">
<xsl:template match="/">
<xsl:variable name="items"
select="('Matthew','Mark','Luke','Matthew','John')"/>
<xsl:value-of select="$items[position() = index-of($items,.)[1]]"/>
</xsl:template>
</xsl:stylesheet>
If I'm not allowed to put the sequence into a variable, but I am
allowed to duplicate the sequence in the expression:
T:\ftemp>xslt2 david2.xsl david2.xsl
<?xml version="1.0" encoding="UTF-8"?>Matthew Mark Luke John
T:\ftemp>type david2.xsl
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform";
version="2.0">
<xsl:template match="/">
<xsl:value-of
select="('Matthew','Mark','Luke','Matthew','John')[position() =
index-of(('Matthew','Mark','Luke','Matthew','John'),.)[1]]"/>
</xsl:template>
</xsl:stylesheet>
T:\ftemp>
I don't think I can do it otherwise, but I only have five minutes
this evening to look at this.
I hope this helps.
. . . . . . . . . . Ken
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