Sorting uniquely

[Donar]

Good day forum!There I am thinking I understood xsl:for-each and xsl:sort. A day later, after a zillion unsuccessful attempts I turn to you in search for help. Maybe you can help me with an approach I did not think of.I am looking to process an unsorted list having multiple identical keys into a sorted list, in which each key appears just once, or in other words, I want to eliminate all dupes, e.g.:

<list><item><key>C</key>...</item><item><key>A</key>...</item><item><key>B</key>...</item><item><key>A</key>...</item></list>

should transform to

<list><item><key>A</key></item><item><key>B</key></item><item><key>C</key></item></list>

(it does not matter which of the 2 "A" nodes is discarded.)Looking forward to your suggestions!Thanks in advance!

[Martin Honnen]

With XSLT 2.0 (as implemented by Saxon 9 or AltovaXML Tools or XQSharp) you can simply use

<xsl:stylesheet  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"  version="2.0">    <xsl:output indent="yes"/>    <xsl:template match="list">	<xsl:copy>	  <xsl:for-each-group select="item" group-by="key">		<xsl:sort select="current-grouping-key()"/>		<item><xsl:copy-of select="key"/></item>	 </xsl:for-each-group>	</xsl:copy>  </xsl:template>  </xsl:stylesheet>

With XSLT 1.0 you can use Muenchian grouping

<xsl:stylesheet  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"  version="1.0">    <xsl:output indent="yes"/>    <xsl:key name="k1" match="item" use="key"/>    <xsl:template match="list">	<xsl:copy>	  <xsl:for-each select="item[generate-id() = generate-id(key('k1', key)[1])]">		<xsl:sort select="key"/>		<item><xsl:copy-of select="key"/></item>	 </xsl:for-each>	</xsl:copy>  </xsl:template>  </xsl:stylesheet>

[Donar]

XSLT 1.0 it is.Thank you very much, it works for me. The final intention is to process an inner loop within the now possible outer loop:b:1a:2c:3a:4should givea:2, 4b:1c:3Then my inner loop looks like this:<xsl:for-each select="key('key', .)">and everything is absolutely fine.My 2 quite thick XML books did make no mention about generate-id() and key(), or even Muenchian grouping, so I did not know they existed (and hence had no idea about googling them). Can you recommend a good XSLT book (English or German)?Thanks again!

[Martin Honnen]

Check http://www.jenitennison.com/xslt/index.html, if you like the explanations there then you might like her books listed also on that page.And of course Michael Kay's XSLT and XPath references from Wrox (http://www.wrox.com/WileyCDA/WroxTitle/XSLT-2-0-and-XPath-2-0-Programmer-s-Reference-4th-Edition.productCd-0470192747.html for XSLT and XPath 2.0, http://www.wrox.com/WileyCDA/WroxTitle/XSL...0764543814.html for XSLT 1.0) surely list anything you ever need to know about XSLT and XPath but these are reference style books, not necessarily suitable for an introduction.

[Donar]

Ordered "XSLT and XPath On The Edge" and looking forward to it.Thank you!