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XSLT checking values in multiple nodes

I have the following XML, which I need to extract the param value based on a child node attribute using XSLT. In this case extract a list of the activities my students are part of:

XML

<students>
   <student id="1000020001"/>  
   <student id="1000020002"/>      
</students>   
<activities>
    <activity name="yoga beginners" start="2016-10-12" end="2016-12-17">          
         <members>            
              <member id="1000020001"/>              
         </members>
    </activity>
    <activity name="yoga intermediate" start="2017-10-12" end="2017-12-17">          
         <members>            
              <member id="1000020001"/>  
              <member id="1000020002"/>            
         </members>
    </activity>
</activities>

I want to create an XSLT which display the activities my students are part of, in this case I have:

XSLT For each student:

<xsl:for-each select="/activities/activity">
   <b>Activity:</b>: 
   <xsl:call-template name="extractActivities">
      <xsl:with-param name="student-id" select="@id"/>
   </xsl:call-template>            
</xsl:for-each>

<xsl:template name="extractActivities">
    <xsl:param name="student-id"/>
    <xsl:if test="$student-id = /activities/activity/members/member/@id">
        <xsl:value-of select="@name"/>
    </xsl:if>
</xsl:template>

I have the following two problems:

  1. First XSLT displays "Activity:" twice as is doing the loop for each node.
  2. No activity name is displayed
Solution

  • It is best to resolve cross-references by using a key:

    XSLT 1.0

    <xsl:stylesheet version="1.0" 
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="html" encoding="UTF-8" />

<xsl:key name="act" match="activity" use="members/member/@id" />

<xsl:template match="/root">
    <html>
        <body>
            <xsl:for-each select="students/student">
                <h3>Student: <xsl:value-of select="@id" /></h3>
                <xsl:for-each select="key('act', @id)">
                    <b>Activity: </b><xsl:value-of select="@name" />
                    <br/>
                </xsl:for-each>
            </xsl:for-each>
        </body>
    </html>
</xsl:template>

</xsl:stylesheet>

    Applied to the following well-formed input:

    XML

    <root>
   <students>
      <student id="1000020001"/>
      <student id="1000020002"/>
   </students>
   <activities>
      <activity name="yoga beginners" start="2016-10-12" end="2016-12-17">
         <members>
            <member id="1000020001"/>
         </members>
      </activity>
      <activity name="yoga intermediate" start="2017-10-12" end="2017-12-17">
         <members>
            <member id="1000020001"/>
            <member id="1000020002"/>
         </members>
      </activity>
   </activities>
</root>

    the result will be:

    <html>
<body>
<h3>Student: 1000020001</h3>
<b>Activity: </b>yoga beginners<br>
<b>Activity: </b>yoga intermediate<br>
<h3>Student: 1000020002</h3>
<b>Activity: </b>yoga intermediate<br>
</body>
</html>