XSLT, 2nd Edition

Grouping with <xsl:variable>

We mentioned earlier that sometimes <xsl:variable> is useful for grouping, so let’s try that approach. We’ll save the value of the <zip> element each time through the <xsl:for-each> element and use preceding-sibling in a slightly different way. Here’s how attempt number three looks:

<?xml version="1.0"?>
<!-- namegrouper3.xsl -->
<xsl:stylesheet version="1.0" 
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

  <xsl:output method="text" indent="no"/>

  <xsl:template match="/">
    <xsl:text>Addresses sorted by zip code&#xA;</xsl:text>
    <xsl:for-each select="addressbook/address">
      <xsl:sort select="zip"/>
      <xsl:variable name="lastZip" select="zip"/>
      <xsl:if test="not(preceding-sibling::address[zip=$lastZip])">
        <xsl:text>Zip code </xsl:text>
        <xsl:value-of select="zip"/>
        <xsl:text>: &#xA;</xsl:text>
        <xsl:for-each select="/addressbook/address[zip=$lastZip]">
          <xsl:sort select="name/last-name"/>
          <xsl:sort select="name/first-name"/>
          <xsl:if test="name/title">
            <xsl:value-of select="name/title"/>
            <xsl:text> </xsl:text>
          </xsl:if>
          <xsl:value-of select="name/first-name"/>
          <xsl:text> </xsl:text>
          <xsl:value-of select="name/last-name"/>
          <xsl:text>&#xA;</xsl:text>
          <xsl:value-of select="street"/>
          <xsl:text>&#xA;&#xA;</xsl:text>
        </xsl:for-each>
      </xsl:if>
    </xsl:for-each>
  </xsl:template>
</xsl:stylesheet>

This stylesheet generates what we want:

Addresses sorted by Zip Code Zip code 00218: Ms. Natalie Attired 707 Breitling Way Zip code 02718: Harry Backstayge 283 First Avenue Mary Backstayge ...