Question

I have the following XML:

<root>
  <row>
    <elem>Timestamp</elem>
    <elem>ERB.CHW.BTU_CV</elem>
    <elem>ERB.CHW.BTU1_CV</elem>
    <elem>ERB.HW.BTU_CV</elem>
    <elem>ERB.HW.BTU1_CV</elem>
    <elem>ERB.KW.DEMAND_CV</elem>
    <elem>ERB.KWH.MT_CV</elem>
    <elem></elem>
  </row>
  <row>
    <elem>2011/09/30 11:21:13.9062</elem>
    <elem>2.307609E+09</elem>
    <elem>1880067</elem>
    <elem>1.068635E+08</elem>
    <elem>1340.386</elem>
    <elem>448.8</elem>
    <elem>1427723</elem>
    <elem></elem>
  </row>
</root>

I want to alter it such that the first <row> defines new elements (via <elem>) and each non-empty <elem> that follows provides values – such as:

<root>
  <row>
    <Timestamp>2011/09/30 11:21:13.9062</Timestamp>
    <ERB.CHW.BTU_CV>2.307609E+09</ERB.CHW.BTU_CV>
    <ERB.CHW.BTU1_CV>1880067</ERB.CHW.BTU1_CV>
    <ERB.HW.BTU_CV>1.068635E+08</ERB.HW.BTU_CV>
    <ERB.HW.BTU1_CV>1340.386</ERB.HW.BTU1_CV>
    <ERB.KW.DEMAND_CV>448.8</ERB.KW.DEMAND_CV>
    <ERB.KWH.MT_CV>1427723</ERB.KWH.MT_CV>
  </row>
</root>

Two things to note:

1. Notice how blank <elem> elements are removed from the source structure.
2. This should work for any number of <row> nodesets.

I feel like this should be simple, but I’m struggling to even know where to begin. Help?

EDIT: RE: #2 above, I am not looking to duplicate the initial <row> nodeset (which is used to define the new elements). Rather, the solution should work for any <row> nodeset that contains data points (i.e., if the second <row> nodeset was duplicated 5 times in a row).

Answer 1

This transformation:

<xsl:stylesheet version="1.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
 <xsl:output omit-xml-declaration="yes" indent="yes"/>
 <xsl:strip-space elements="*"/>

 <xsl:variable name="vElems" select=
     "/*/row[1]/elem[normalize-space()]"/>


 <xsl:template match="/*">
  <root>
    <xsl:apply-templates select="row[position() >1]"/>
  </root>
 </xsl:template>

 <xsl:template match="row">
  <row>
   <xsl:apply-templates select="$vElems">
    <xsl:with-param name="pValues"
      select="elem"/>
    </xsl:apply-templates>
  </row>
 </xsl:template>

 <xsl:template match="elem">
  <xsl:param name="pValues"/>
  <xsl:variable name="vPos" select="position()"/>

  <xsl:element name="{.}">
   <xsl:value-of select="$pValues[$vPos]"/>
  </xsl:element>
 </xsl:template>
</xsl:stylesheet>

when applied on the following XML document (the provided plus one more data row):

<root>
    <row>
        <elem>Timestamp</elem>
        <elem>ERB.CHW.BTU_CV</elem>
        <elem>ERB.CHW.BTU1_CV</elem>
        <elem>ERB.HW.BTU_CV</elem>
        <elem>ERB.HW.BTU1_CV</elem>
        <elem>ERB.KW.DEMAND_CV</elem>
        <elem>ERB.KWH.MT_CV</elem>
        <elem></elem>
    </row>
    <row>
        <elem>2011/09/30 11:21:13.9062</elem>
        <elem>2.307609E+09</elem>
        <elem>1880067</elem>
        <elem>1.068635E+08</elem>
        <elem>1340.386</elem>
        <elem>448.8</elem>
        <elem>1427723</elem>
        <elem></elem>
    </row>
    <row>
        <elem>2011/09/31 11:22:33.9063</elem>
        <elem>3.418609E+10</elem>
        <elem>1991073</elem>
        <elem>1.068635E+08</elem>
        <elem>1340.386</elem>
        <elem>452.5</elem>
        <elem>169578</elem>
        <elem></elem>
    </row>
</root>

produces the wanted, correct result:

<root>
   <row>
      <Timestamp>2011/09/30 11:21:13.9062</Timestamp>
      <ERB.CHW.BTU_CV>2.307609E+09</ERB.CHW.BTU_CV>
      <ERB.CHW.BTU1_CV>1880067</ERB.CHW.BTU1_CV>
      <ERB.HW.BTU_CV>1.068635E+08</ERB.HW.BTU_CV>
      <ERB.HW.BTU1_CV>1340.386</ERB.HW.BTU1_CV>
      <ERB.KW.DEMAND_CV>448.8</ERB.KW.DEMAND_CV>
      <ERB.KWH.MT_CV>1427723</ERB.KWH.MT_CV>
   </row>
   <row>
      <Timestamp>2011/09/31 11:22:33.9063</Timestamp>
      <ERB.CHW.BTU_CV>3.418609E+10</ERB.CHW.BTU_CV>
      <ERB.CHW.BTU1_CV>1991073</ERB.CHW.BTU1_CV>
      <ERB.HW.BTU_CV>1.068635E+08</ERB.HW.BTU_CV>
      <ERB.HW.BTU1_CV>1340.386</ERB.HW.BTU1_CV>
      <ERB.KW.DEMAND_CV>452.5</ERB.KW.DEMAND_CV>
      <ERB.KWH.MT_CV>169578</ERB.KWH.MT_CV>
   </row>
</root>