Dynamically Reference Position within Absolute Path in XSL

Question

All---
I have a file that I am parsing into many records. However, much of the information is duplicated and I do not want to considerate for my XSL. For this reason, I need to add logic to filter out those records that have the same account number as the previous record. It would seem that the best way to do this would be an "if" statement that compares the account number from the record in question to the account number in the previous record. This is what I have come up with:
<xsl:for-each select="/imp1:container/imp1:Record">
<xsl:if test='(position() = "1") or (imp1:Patient/imp1:AccountNumber != /imp1:container/imp1:Record[(position() - 1.0)]/imp1:Patient/imp1:AccountNumber)'>
As you may have guessed, this does not work. Any thoughts?
Thanks, Eric

Answer 1

I tried my solution with Saxon 8.8 and Oracle XDK 10.2.0.2
I created a source XML document of:
<container xmlns="urn:foo">
  <Record>
    <Patient>
       <AccountNumber>101</AccountNumber>
       <Something>Y</Something>
    </Patient>
  </Record>
  <Record>
    <Patient>
       <AccountNumber>101</AccountNumber>
       <Something>Y</Something>
    </Patient>
  </Record>
  <Record>
    <Patient>
       <AccountNumber>102</AccountNumber>
       <Something>Y</Something>
    </Patient>
  </Record>
</container>and an XSLT stylesheet of:
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
                xmlns:imp1="urn:foo" version="1.0">
  <xsl:output method="text"/>
  <xsl:template match="/">
  <xsl:for-each select="/imp1:container/imp1:Record">
    <xsl:variable name="prevRec" select="preceding-sibling::imp1:Record"/>
    <xsl:variable name="curAcctNum" select="imp1:Patient/imp1:AccountNumber"/>
    <xsl:variable name="prevAcctNum" select="$prevRec/imp1:Patient/imp1:AccountNumber"/>
    <xsl:if test='not($prevRec) or $curAcctNum != $prevAcctNum'>
       <!-- etc. -->
       <xsl:value-of select="imp1:Patient/imp1:AccountNumber"/>
       <xsl:text>&#xa;</xsl:text>
    </xsl:if>
  </xsl:for-each>
  </xsl:template>
</xsl:stylesheet>Which produces an output on the command line of:
101
102So it seems to be correctly ignoring the duplicate entries. Is something about my test source data not mimicking faithfully enough your situation?