Grouping XML with child attribute with XSLT1.0

Question

Im now to XSLT and I need to do some grouping with the value of a child. I have objects, that can have multiple properties and one of them (with id=11) is on I need to use as a grouping element. The amount of properties each object can have varies, but they all have the common prop.

Input:

<object id=1>
 <properties>
    <prop id=10>Name of object 1</prop>
    <prop id=11>Group 1</prop>
    <prop id=xy>Whatever properties this object has</prop>
 </properties>
</object>
<object id=2>
 <properties>
    <prop id=10>Name of object 2</prop>
    <prop id=11>Group 2</prop>
 </properties>
</object>
<object id=3>
 <properties>
    <prop id=10>Name of object 3</prop>
    <prop id=11>Group 1</prop>
 </properties>
</object>
<object id=4>
 <properties>
    <prop id=10>Name of object 4</prop>
    <prop id=11>Group 3</prop>
 </properties>
</object>

Desired output:

<group name='Group 1'>
  <object id=1>
    <prop id=10>Name of object 1</prop>
    <prop id=11>Group 1</prop>
    <prop id=xy>Whatever properties this object has</prop>
  </object>
<object id=3>
 <properties>
    <prop id=10>Name of object 3</prop>
    <prop id=11>Group 1</prop>
 </properties>
</object>
</group>
<group name='Group 2'>
  <object id=2>
   <properties>
    <prop id=10>Name of object 2</prop>
    <prop id=11>Group 2</prop>
   </properties>
  </object>
</group>
<group name='Group 3'>
  <object id=4>
   <properties>
    <prop id=10>Name of object 4</prop>
    <prop id=11>Group 3</prop>
   </properties>
  </object>
</group>

The idea is to have the items grouped by the value of the prop with id 11.

Ive found multiple different code samples, but none of them have had this specific case, and I havent been able to modify them to suit my need.

By the way, this is pretty much the same question as stackoverflow.com/questions/2291567/…. — Michael Vehrs
– Michael Vehrs, Commented Jul 6, 2016 at 13:22

Phil Blackburn · Accepted Answer · 2016-07-07 10:06:20Z

2

My version of the xsl that is essentially that same as Michael Vehrs in that it is also using the Muenchian Method but thought I may as well post it to show a subtle alternative. Here I'm using an apply-templates instead of the for-each/call-template. In terms of performance there is probably nothing between them but personally, I prefer to use apply-templates wherever possible as it typically allows for more flexibility.

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" indent="no" encoding="utf-8"/>
<xsl:key name="groups" match="prop[@id='11']" use="text()"/>

<xsl:template match="/">
    <xsl:apply-templates select="//prop[generate-id()=generate-id(key('groups', text())[1])]"/>
</xsl:template>

<xsl:template match="prop">
    <group name="{text()}">
        <xsl:copy-of select="//object[properties/prop[@id='11']=current()/text()]"/>
    </group>
</xsl:template>

</xsl:stylesheet>

answered Jul 7, 2016 at 10:06

Phil Blackburn

1,0671 gold badge8 silver badges13 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Kemu79 Over a year ago

Apply-templates seems like the more straightforward option and this worked perfectly.

Michael Vehrs · Accepted Answer · 2016-07-07 09:01:37Z

This is a basic application of the Muenchian Method (which is explained here, for example):

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

<xsl:key name="prop" match="//prop[@id='11']/text()" use="." />

<xsl:template match="/">
  <xsl:for-each select="//prop[@id='11']/text()[generate-id()
                        = generate-id(key('prop',.)[1])]">
    <xsl:call-template name="group">
      <xsl:with-param name="groupname" select="." />
    </xsl:call-template>
  </xsl:for-each>
</xsl:template>

<xsl:template name="group">
  <xsl:param name="groupname" />
  <group><xsl:attribute name="name"><xsl:value-of select='$groupname'/></xsl:attribute>
  <xsl:for-each select="//object[.//prop[@id='11'][text()=$groupname]]" >
    <xsl:copy-of select="." />
  </xsl:for-each>
  </group>
</xsl:template>

</xsl:stylesheet>

Collectives™ on Stack Overflow

Grouping XML with child attribute with XSLT1.0

2 Answers 2

1 Comment

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related