Using XPATH to compute the minimum attribute element and add it to another attribute

Question

My question is similar to this one, in which the author asks how to find the minimum attribute of an set of elements. I'm a beginner at xpath and I'm having trouble taking that answer and adding it to my XSLT. I need to find the minimum price of a Plan (see below) and add an attribute to the Subdivision containing that minimum.

I have the following XML snippet:

<Subdivision Status="Active">
  <SubdivisionName>Chesla</SubdivisionName>
  <Plan Type="SingleFamily">
    <PlanNumber>555</PlanNumber>
    <PlanName>Pinewood</PlanName>
    <BasePrice>200500.0000</BasePrice>
  </Plan>
  <Plan Type="MultiFamily">
    <PlanNumber>444</PlanNumber>
    <PlanName>Westfield</PlanName>
    <BasePrice>270000.0000</BasePrice>
  </Plan>

Note: There can be multiple Subdivisions in my XML document. I'm just showing one in my example for the sake of brevity.

My final output is the same as the input except that a PriceLow attribute has been added to the Subdivision element containing the minimum BasePrice of all Plans who are siblings of the Subdivision:

<Subdivision Status="Active" PriceLow="200500.00"> <==== ADDED!!!
  <SubdivisionName>Chesla</SubdivisionName>
  <Plan Type="SingleFamily">
    <PlanNumber>555</PlanNumber>
    <PlanName>Pinewood</PlanName>
    <BasePrice>200500.00</BasePrice>
  </Plan>
  <Plan Type="MultiFamily">
    <PlanNumber>444</PlanNumber>
    <PlanName>Westfield</PlanName>
    <BasePrice>270000.00</BasePrice>
  </Plan>

My incomplete xsl file looks like this:

<xsl:output omit-xml-declaration="yes" indent="yes"/>

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

<xsl:template match="Subdivision">
   ... something goes here ...
</xsl:template>

Could someone help me complete this XSLT file? I'm reading a few books on XSLT, but in the meantime I need to complete this project soon.

Cheers, Bret

JLRishe · Accepted Answer · 2013-04-15T22:24:09.140

This should do it:

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

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

  <xsl:template match="Subdivision">
    <xsl:copy>
      <xsl:apply-templates select="@*" />
      <xsl:attribute name="PriceLow">
        <xsl:apply-templates select="Plan/BasePrice" mode="min">
          <xsl:sort select="." order="ascending" data-type="number" />
        </xsl:apply-templates>
      </xsl:attribute>

      <xsl:apply-templates select="node()" />
    </xsl:copy>
  </xsl:template>

  <xsl:template match="node()" mode="min">
    <xsl:if test="position() = 1">
      <xsl:value-of select="."/>
    </xsl:if>
  </xsl:template>
</xsl:stylesheet>

Or a more succinct, but possibly less efficient approach:

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

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

  <xsl:template match="Subdivision">
    <Subdivision PriceLow="{Plan/BasePrice[not(. > current()/Plan/BasePrice)]}">
      <xsl:apply-templates select="@*[name() != 'PriceLow'] | node()" />
    </Subdivision>
  </xsl:template>
</xsl:stylesheet>

When either of these is run on this sample data:

<root>
  <Subdivision Status="Active">
    <SubdivisionName>Chesla</SubdivisionName>
    <Plan Type="SingleFamily">
      <PlanNumber>555</PlanNumber>
      <PlanName>Pinewood</PlanName>
      <BasePrice>200500.0000</BasePrice>
    </Plan>
    <Plan Type="MultiFamily">
      <PlanNumber>444</PlanNumber>
      <PlanName>Westfield</PlanName>
      <BasePrice>270000.0000</BasePrice>
    </Plan>
  </Subdivision>

  <Subdivision Status="Active">
    <SubdivisionName>Newhaven</SubdivisionName>
    <Plan Type="SingleFamily">
      <PlanNumber>555</PlanNumber>
      <PlanName>Pinewood</PlanName>
      <BasePrice>200900.0000</BasePrice>
    </Plan>
    <Plan Type="MultiFamily">
      <PlanNumber>444</PlanNumber>
      <PlanName>Westfield</PlanName>
      <BasePrice>200100.0000</BasePrice>
    </Plan>
    <Plan Type="QuadrupleFamily">
      <PlanNumber>111</PlanNumber>
      <PlanName>Pinewood</PlanName>
      <BasePrice>200050.0000</BasePrice>
    </Plan>
    <Plan Type="QuintupleFamily">
      <PlanNumber>222</PlanNumber>
      <PlanName>Pinewood</PlanName>
      <BasePrice>200300.0000</BasePrice>
    </Plan>
  </Subdivision>
</root>

The result is:

<root>
  <Subdivision Status="Active" PriceLow="200500.0000">
    <SubdivisionName>Chesla</SubdivisionName>
    <Plan Type="SingleFamily">
      <PlanNumber>555</PlanNumber>
      <PlanName>Pinewood</PlanName>
      <BasePrice>200500.0000</BasePrice>
    </Plan>
    <Plan Type="MultiFamily">
      <PlanNumber>444</PlanNumber>
      <PlanName>Westfield</PlanName>
      <BasePrice>270000.0000</BasePrice>
    </Plan>
  </Subdivision>

  <Subdivision Status="Active" PriceLow="200050.0000">
    <SubdivisionName>Newhaven</SubdivisionName>
    <Plan Type="SingleFamily">
      <PlanNumber>555</PlanNumber>
      <PlanName>Pinewood</PlanName>
      <BasePrice>200900.0000</BasePrice>
    </Plan>
    <Plan Type="MultiFamily">
      <PlanNumber>444</PlanNumber>
      <PlanName>Westfield</PlanName>
      <BasePrice>200100.0000</BasePrice>
    </Plan>
    <Plan Type="QuadrupleFamily">
      <PlanNumber>111</PlanNumber>
      <PlanName>Pinewood</PlanName>
      <BasePrice>200050.0000</BasePrice>
    </Plan>
    <Plan Type="QuintupleFamily">
      <PlanNumber>222</PlanNumber>
      <PlanName>Pinewood</PlanName>
      <BasePrice>200300.0000</BasePrice>
    </Plan>
  </Subdivision>
</root>

Using XPATH to compute the minimum attribute element and add it to another attribute

1 Answers1