How do I combine or merge grouped nodes? - xslt

Question

Using the XSL:
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:xs="http://www.w3.org/2001/XMLSchema" exclude-result-prefixes="xs" version="2.0">
<xsl:output method="xml"/>
<xsl:template match="/">
<records>
<record>
<!-- Group record by bigID, for further processing -->
<xsl:for-each-group select="records/record" group-by="bigID">
<xsl:sort select="bigID"/>
<xsl:for-each select="current-group()">
<!-- Create new combined record -->
<bigID>
<!-- <xsl:value-of select="."/> -->
<xsl:for-each select=".">
<xsl:value-of select="bigID"/>
</xsl:for-each>
</bigID>
<text>
<xsl:value-of select="text"/>
</text>
</xsl:for-each>
</xsl:for-each-group>
</record>
</records>
</xsl:template>
</xsl:stylesheet>
I'm trying to change:
<?xml version="1.0" encoding="UTF-8"?>
<records>
<record>
<bigID>123</bigID>
<text>Contains text for 123</text>
<bigID>456</bigID>
<text>Some 456 text</text>
<bigID>123</bigID>
<text>More 123 text</text>
<bigID>123</bigID>
<text>Yet more 123 text</text>
</record>
</records>
into:
<?xml version="1.0" encoding="UTF-8"?>
<records>
<record>
<bigID>123
<text>Contains text for 123</text>
<text>More 123 text</text>
<text>Yet more 123 text</text>
</bigID>
<bigID>456
<text>Some 456 text</text>
</bigID>
</record>
</records>
Right now, I'm just listing the grouped <bigID>s, individually. I'm missing the step after grouping, where I combine the grouped <bigID> nodes. My suspicion is that I need to use the "key" function somehow, but I'm not sure.
Thanks for any help.

Answer 1

Here is the wanted XSLT 2.0 transformation:
<xsl:stylesheet version="2.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
>
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:key name="kTextforId" match="text"
use="preceding-sibling::bigID[1]"/>
<xsl:template match="node()|#*">
<xsl:copy>
<xsl:apply-templates select="node()|#*"/>
</xsl:copy>
</xsl:template>
<xsl:template match="record">
<record>
<xsl:for-each-group select="bigID" group-by=".">
<bigID>
<xsl:sequence select="current-grouping-key()"/>
<xsl:copy-of select=
"key('kTextforId', current-grouping-key())"/>
</bigID>
</xsl:for-each-group>
</record>
</xsl:template>
</xsl:stylesheet>
When performed on the provided XML document, the wanted result is produced.

Answer 2

In XSLT 2.0 you don't need keys for grouping.
Since you are just copying the text elements in the group, the inner for-each can be removed.
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" indent="yes" />
<xsl:template match="/">
<records>
<record>
<xsl:for-each-group select="records/record/bigID" group-by=".">
<xsl:sort select="." data-type="number" />
<bigID>
<xsl:value-of select="." />
<xsl:copy-of select="current-group()/following-sibling::text[1]" />
</bigID>
</xsl:for-each-group>
</record>
</records>
</xsl:template>
</xsl:stylesheet>
If you instead wanted to output the bigID elements followed by their text elements, then my loop would be replaced by the following.
<xsl:for-each-group select="records/record/bigID" group-by=".">
<xsl:sort select="." data-type="number" />
<xsl:copy-of select="." />
<xsl:copy-of select="current-group()/following-sibling::text[1]" />
</xsl:for-each-group>