Re: sum of products

> How do you write the xpath to calculate the sum or a*b for the

this is a faq.

You can not do it in a single xpath.

easiest is to generate a result tree fragment with the list of products

<xsl:variable name="x">
 <xsl:for-each select="item/data[@id=2]">
  <x><xsl:value-of select="a * b"/></x>
 </xsl:for-each>
</xsl:variable>

then use your processors node-set() extension to sum

<xsl:value-of select="sum(xx:node-set($x)/x"/>

David

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