How to add two variables in XSLT

[Anil Vupputuri]

Hi All,
I've two variables var1 and var2, how can I add them up.


For eg.,

var1 = 5
var2 = 5

var3 = var1 + var2
= 10

<xsl:value-of name="var3" select="$var1+$var2"/> doesn't work.

Thanks.

[Paul Clapham]

Quote from the XPath Recommendation:

The + operator performs addition.

I think your example doesn't work because the xsl:value-of element can't have a "name" attribute.

Later: Oh, I see, you want to know how to assign the sum to a variable named "var3". You use the <xsl:variable> element to declare a variable and assign a value to it. Remember that these two must always be done at the same time in XSLT, you can't declare a variable and later assign it a value. So:

<xsl:variable name="var3" select="$var1 + $var2"/>

[ May 24, 2006: Message edited by: Paul Clapham ]

[Anil Vupputuri]

Thanks Paul.

But the following piece of code doesn't work.

   <xsl:variable name="var3" select="$var1 + $var2"/>
 

How to get total from var1 and var2?

[Paul Clapham]

Could you provide some useful information other than "doesn't work"?

[Anil Vupputuri]

Here is the more descriptive code,

    
      <xsl:variable name="total-ytd-max-installed"/> 
 
      <xsl:for-each select="document('../xml/ytd_usage.xml')/sniffer-license-usage/feature">          
 
       <xsl:variable name="ytd-max-installed" select="ytd-max-installed"/>
       <td> <xsl:value-of select="$ytd-max-installed"/> </td>
       <xsl:if test="$ytd-max-installed != 'NA'">
       
        <xsl:variable name="total-ytd-max-installed" select="$total-ytd-max-installed + $ytd-max-installed"/> 
       
       </xsl:if>
</xsl:for-each> 
       

When we tried to print the value of "total-ytd-max-installed", its giving nothing. Following is the code to display the value,

 <xsl:value-of select="$total-ytd-max-installed"/>   

Thanks.

[Paul Clapham]

Ah well, finally we have the real question. You didn't notice what I said before, did you?

"Remember that these two must always be done at the same time in XSLT, you can't declare a variable and later assign it a value."

Let's look at your code...

<xsl:variable name="total-ytd-max-installed"/>
  (Here you declare a variable that has no value, and never will have one.) 
<xsl:for-each select="document('../xml/ytd_usage.xml')/sniffer-license-usage/feature">          
 
  <xsl:variable name="ytd-max-installed" select="ytd-max-installed"/>
    (Here you declare another variable, and assign it itself as its value.)
    (Note that its scope is limited to the xsl:for-each element it's in.)
  <td> <xsl:value-of select="$ytd-max-installed"/> </td>
  <xsl:if test="$ytd-max-installed != 'NA'">
 
    <xsl:variable name="total-ytd-max-installed" select="$total-ytd-max-installed + $ytd-max-installed"/>
      (Here you declare a third variable, and assign itself plus itself to it.)
      (Note that its scope is limited to the xsl:if element it's in.)
  </xsl:if>
</xsl:for-each>
  (At this point there's only one $ytd-max-installed variable in scope.)
  (And you never initialized it.)

The standard way to assign the sum of some things to a variable in XSLT is via a recursive method. Here's an article that explains that sort of thing:

http://www-128.ibm.com/developerworks/xml/library/x-xslrecur/

"Recursion Example 1" is quite similar to what you want to do.

[Clifton Craig]

Originally posted by Anil Vupputuri:
[QB]Here is the more descriptive code,

    
      <xsl:variable name="total-ytd-max-installed"/> 
 
      <xsl:for-each select="document('../xml/ytd_usage.xml')/sniffer-license-usage/feature">          
 
       <xsl:variable name="ytd-max-installed" select="ytd-max-installed"/>
       <td> <xsl:value-of select="$ytd-max-installed"/> </td>
       <xsl:if test="$ytd-max-installed != 'NA'">
       
        <xsl:variable name="total-ytd-max-installed" select="$total-ytd-max-installed + $ytd-max-installed"/> 
       
       </xsl:if>
</xsl:for-each> 
       

Also I didn't see an alternative condition in your code. What do you do when $ytd-max-installed is equal to 'NA'? I would use xsl:choose to ensure $total-ytd-max-installed had a value. Something like this:

<xsl:for-each select="document('../xml/ytd_usage.xml')/sniffer-license-usage/feature">          
 
   <xsl:variable name="ytd-max-installed" select="ytd-max-installed"/>
   <td> <xsl:value-of select="$ytd-max-installed"/> </td>
   <xsl:variable name="total-ytd-max-installed">
      <xsl:choose>
         <xsl:when test="$ytd-max-installed != 'NA'">
            <xsl:value-of select="$total-ytd-max-installed + $ytd-max-installed"/> 
         </xsl:when>
         <otherwise><xsl:text>N/A</xsl:text></otherwise>
      </xsl:choose>
   </xsl:variable>
   <!-- use $total-ytd-max-installed here... -->
</xsl:for-each> 

Also it looks like maybe you would want to increment $total-ytd-max-installed. You probably want to declare $total-ytd-max-installed outside the loop and set it with something like:

sum(document('../xml/ytd_usage.xml')/sniffer-license-usage/feature/ytd-max-installed[text()!='N/A'])

That's from the top of my head and untested but I hope you get the idea.