XSLT: attribute sorting

Question

I need help with a small example, so that I can understand xsl:sort better.

My XML data looks like:

<NewTerms>
    <newTerm ID="3">Zebra</newTerm>
    <newTerm ID="11">Horse</newTerm>
    <newTerm ID="1">Cat</newTerm>
    <newTerm ID="90">Lion</newTerm>
    <newTerm ID="62">Jaguar</newTerm>
    <newTerm ID="30">Cheetah</newTerm>
    <newTerm ID="55">Deer</newTerm>
    <newTerm ID="45">Buffalo</newTerm>
    <newTerm ID="15">Dog</newTerm>
</NewTerms ID="10">

and I want to sort them according to the ID attribute. The XSL that I have is not working:

<?xml version="1.0"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">

    <xsl:output method="xml" indent="yes" omit-xml-declaration="no"/>

    <xsl:template match="@*|node()[not(preceding::node()=.)]">
        <xsl:copy>
            <xsl:apply-templates select="@*|node()[not(preceding::node()=.)]">
                <xsl:sort select="./@ID"/>
            </xsl:apply-templates>
        </xsl:copy>
    </xsl:template>

</xsl:stylesheet>

I don't know how the xsl:sort function works. Help me through this example to get a better understanding of it.

Nice to see an attribute in an [End-Tag](http://www.w3.org/TR/1998/REC-xml-19980210#NT-ETag) :D — Emiliano Poggi, Jun 28 '11 at 19:48

score 4 · Answer 1 · edited May 23 '17 at 11:43

Your transform is correct. You have missed only to specify the data-type attribute which by default is "text" thus not working with numbers.

For more information about using xsl:sort you can see the specs and a recent similar question.

Here a few notes:

You can omit the ./@ID because . selects the context node which is the default in the template
You don't need to check for preceding nodes in that way, it does not make sense.

Notice You need only the Identity Transformation with a sort instruction.

Your final transform will look like:

<xsl:stylesheet
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform" 
    version="1.0">

    <xsl:output method="xml" indent="yes" omit-xml-declaration="no"/>
    <xsl:strip-space elements="*"/>

  <xsl:template match="@*|node()">
    <xsl:copy>
      <xsl:apply-templates select="@*|node()">
                <xsl:sort select="@ID" data-type="number"/>
      </xsl:apply-templates>
     </xsl:copy>
  </xsl:template>

</xsl:stylesheet>

When applied to the input (here a bit modified to fix your end-tag typo):

<NewTerms>   
    <newTerm ID="3">Zebra</newTerm>
    <newTerm ID="11">Horse</newTerm> 
    <newTerm ID="1">Cat</newTerm>   
    <newTerm ID="90">Lion</newTerm>   
    <newTerm ID="62">Jaguar</newTerm>   
    <newTerm ID="30">Cheetah</newTerm>   
    <newTerm ID="55">Deer</newTerm>   
    <newTerm ID="45">Buffalo</newTerm>   
    <newTerm ID="15">Dog</newTerm> 
</NewTerms>

produces:

<NewTerms>
   <newTerm ID="1">Cat</newTerm>
   <newTerm ID="3">Zebra</newTerm>
   <newTerm ID="11">Horse</newTerm>
   <newTerm ID="15">Dog</newTerm>
   <newTerm ID="30">Cheetah</newTerm>
   <newTerm ID="45">Buffalo</newTerm>
   <newTerm ID="55">Deer</newTerm>
   <newTerm ID="62">Jaguar</newTerm>
   <newTerm ID="90">Lion</newTerm>
</NewTerms>

rsp · Answer 2 · 2011-06-28T16:13:39.067

1

The ID attribute in your clasing tag of NewTerms seems to be out of place.

The following XSL script sorts your data on the ID attribute:

<xsl:stylesheet version="1.0"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

  <xsl:output method="xml"/>

  <xsl:template match="@*|node()">
    <xsl:copy-of select="." />
  </xsl:template>

  <xsl:template match="/NewTerms">
    <xsl:copy>
      <xsl:apply-templates select="newTerm">
        <xsl:sort select="@ID" data-type="number" />
      </xsl:apply-templates>
     </xsl:copy>
  </xsl:template>

</xsl:stylesheet>

edited Jun 28 '11 at 16:13

answered Jun 28 '11 at 15:53

rsp

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3

Those ID attribute values look like numbers so doing '` is probably necessary to sort as requested. The default data type is "text" and that way for instance "110" would end up before "12". – Martin Honnen Jun 28 '11 at 16:02

score 0 · Answer 3 · answered Jun 28 '11 at 18:12

As was pointed out in the comments to @rsp's answer, the default sort data-type is "text", but you want "number". You could actually use your own first attempt after making just that one change:

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">

  <xsl:output method="xml" indent="yes" omit-xml-declaration="no"/>

  <xsl:template match="@*|node()[not(preceding::node()=.)]">
    <xsl:copy>
      <xsl:apply-templates select="@*|node()[not(preceding::node()=.)]">
        <xsl:sort select="./@ID" data-type="number" />
      </xsl:apply-templates>
     </xsl:copy>
  </xsl:template>

</xsl:stylesheet>

This allows you to keep your (inefficient) duplicate check:

node()[not(preceding::node()=.)]

XSLT: attribute sorting

3 Answers3