Need to determine uniquiness among several attributes

mphare · January 29th, 2010, 11:25 AM

Hi,

I'm using saxon 9.0.0.6J from a Cygwin bash shell on WinXP. I have Oxygen XML v.11, so I have saxon EE in there, but I don't think I can access it from a command line, so for now, I'll be using saxon 9

Here's my problem:

I have a structure where a particular element has 3 attributes
something like:

PHP Code:


			
<root>
  <elem1>
    <elem2 attr1="val1" attr2="val2" attr3="val3">
      <elem3/>
    </elem2>
  </elem1>
  <elem1>
    <elem2 attr1="val1" attr2="val2" attr3="val3">
      <elem3/>
    </elem2>
   </elem1>
   <elem1>
    <elem2 attr1="val1" attr2="val2" attr3="val3">
      <elem3/>
    </elem2>
  </elem1>
...
</root>

and so on..

what I want to do is be sure there is only one unique combination of values for attr1, attr2 and attr3 across all the possible elem2s in the structure.

It looks like a job for groups, but I don't see how to create the select statement to gather the items I'm looking for.

Thanks,

- m

samjudson · January 29th, 2010, 11:44 AM

<xsl:for-each-group select="//elem2" group-by="concat(@attr1,@attr2,@attr2)">

This will give you groups of elements with the came attribute set. THen you can use current-group()[1] to get the first element, and look at its attributes.

Sam

Martin Honnen · January 29th, 2010, 11:53 AM

You could group by some concatenation of the attribute values, as already suggested, although I would use some separator character that is not part of the attribute values, then you could count the number of groups, if it is one then you have the same attribute values on all elements:

Code:

<xsl:stylesheet
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
  version="2.0">
  
  <xsl:param name="sep" select="'|'"/>
  
  <xsl:template match="/">
    <xsl:variable name="groups">
      <xsl:for-each-group select="root/elem1/elem2" group-by="string-join((@attr1, @attr2, @attr3), $sep)">
        <group/>
      </xsl:for-each-group>
    </xsl:variable>
    <xsl:variable name="count" select="count($groups/group)"/>
    <!-- now check $count eq 1 here -->

mphare · January 29th, 2010, 03:02 PM

Thanks for the help.
For what I needed the concat() worked perfectly.