CODEWITHSUNDEEP
xmlxsltxslt-1.0
Suresh
Suresh

Reputation: 1101

XSLT transform with subgroups

My input xml below has many 'a' elements under subroot tag. Whichever 'a' group, having a keyid, not starts with 'ab', should come under the preceding 'a' element, which starts with 'ab'(keyid element). The output will have a new tag 'subdetail'. Here is my desired output. If there is no subgroup, the subdetail elements will be absent in the output. input xml

<Root>
  <subroot>
    <a>
      <keyid>ab123456</keyid>
      <detail>hi</detail>
    </a>
    <a>
      <keyid>09876</keyid>
      <detail>undermain1</detail>
    </a>
    <a>
      <keyid>087564</keyid>
      <detail>undermain2</detail>
    </a>
    <a>
      <keyid>ab4567</keyid>
      <detail>hi</detail>
    </a>
    <a>
      <keyid>056432</keyid>
      <detail>undermain1</detail>
    </a>
  </subroot>
</Root>

desired output

<Root>
  <subroot>
    <a>
      <keyid>ab123456</keyid>
      <detail>hi</detail>
      <subdetail>
        <detail>undermain1</detail>
      </subdetail>
      <subdetail>
        <detail>undermain2</detail>
      </subdetail>
    </a>
    <a>
      <keyid>ab4567</keyid>
      <detail>hi</detail>
      <subdetail>
        <detail>undermain1</detail>
      </subdetail>
    </a>
  </subroot>
</Root>

Upvotes: 0

Views: 95

Answers (1)

Tim C
Tim C

Reputation: 70648

This can be achieved by creating a key to group a elements by the most preceding a element with an 'ab' key

<xsl:key 
   name="a" 
   match="a[not(starts-with(keyid, 'ab'))]" 
   use="generate-id(preceding-sibling::a[starts-with(keyid, 'ab')][1])" />

Then when you match the a elements with an 'ab' key, you can get the other a elements as follows

<xsl:apply-templates select="key('a', generate-id())" />

Here is the full XSLT

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

   <xsl:key name="a" match="a[not(starts-with(keyid, 'ab'))]" use="generate-id(preceding-sibling::a[starts-with(keyid, 'ab')][1])" />

   <xsl:template match="subroot">
      <xsl:apply-templates select="a[starts-with(keyid, 'ab')]" />
   </xsl:template>

   <xsl:template match="a[starts-with(keyid, 'ab')]">
      <a>
         <xsl:apply-templates select="@*|node()" />
         <xsl:apply-templates select="key('a', generate-id())" />
      </a>
   </xsl:template>

   <xsl:template match="a">
      <subdetail>
         <xsl:copy-of select="detail" />
      </subdetail>
   </xsl:template>

   <xsl:template match="@*|node()">
      <xsl:copy>
         <xsl:apply-templates select="@*|node()"/>
      </xsl:copy>
   </xsl:template>
</xsl:stylesheet>

When applied to the sample XML, the following is output

<Root>
   <a>
      <keyid>ab123456</keyid>
      <detail>hi</detail>
      <subdetail>
         <detail>undermain1</detail>
      </subdetail>
      <subdetail>
         <detail>undermain2</detail>
      </subdetail>
   </a>
   <a>
      <keyid>ab4567</keyid>
      <detail>hi</detail>
      <subdetail>
         <detail>undermain1</detail>
      </subdetail>
   </a>
</Root>

Upvotes: 1

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