How can I sum-up the results of a for-each loop in XSL?

Question

I am new to XSL so I don´t really know how to do this. I have a for-each statement that does some computations for each element of a type "cell". How can I sum-up the results and store them in a variable so I can display it? I have included a part of the code.

I hope someone knows the solution to this problem. Thank you for your time and effort!

<?xml version="1.0"?>
<xsl:stylesheet version="1.0">

<xsl:output media-type="xml" encoding="ISO-8859-1" indent="yes"/>

<xsl:key name="object-map" match="/Data/Objects/*" use="@ExternalId"/>
<xsl:template match="/">
 <Data>
  <Objects>
    ...
    ...
    ...

    <xsl:for-each select="Data/Objects/Cell">
   <xsl:attribute name="PpXmlVer">
     <xsl:text>7.0</xsl:text>
   </xsl:attribute>

      ......................

      <!--Calculating Machine Time: -->
      <Cell>
        <xsl:attribute name="ExternalId">
          <xsl:value-of select="@ExternalId"/>
        </xsl:attribute>
        <!-- calculated.-->
        <FlipMachineTime>
          <xsl:choose>
            <xsl:when test="./FlipPlanedOccupationTime &gt; 0">
              <xsl:value-of select="here is a complicated formula to compute"/>
            </xsl:when>
            <xsl:otherwise>0</xsl:otherwise>
          </xsl:choose>
        </FlipMaschineTime>
      </Cell>

      </xsl:for-each>

      Here I would like to have the sum of FlipMachineTime 
      for all encountered elements of type cell.

    ...........

  </Objects>
 </Data>

Answer 1

You need to create a variable to hold the FlipMachineTime nodes you have computed. Then you can sum the nodeset. Here is some sample code:

<xsl:variable name="flipMachineTimes">
  <xsl:for-each select="/Data/Objects/Cell">
    <FlipMachineTime>
      <xsl:choose>
        <xsl:when test="./FlipPlanedOccupationTime > 0">
          <xsl:value-of select="here is a complicated formula to compute"/>
        </xsl:when>
        <xsl:otherwise>0</xsl:otherwise>
      </xsl:choose>
    </FlipMachineTime>
  </xsl:for-each>
</xsl:variable>
<total>
  <xsl:variable name="myTotal" select="xalan:nodeset($flipMachineTimes)"/>
  <xsl:value-of select="sum($myTotal/FlipMachineTime)"/>
</total>

To get this to work, make sure you include the xalan namespace in your stylesheet:

<xsl:stylesheet version="1.0" xmlns:xalan="http://xml.apache.org/xalan" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">