XSLT remove duplicate nodes based on element value

问题:

I am newbie to XSLT.can you help me for xslt to achieve below output. In my input xml have duplicate nodes and i have to remove based on element (CustAccId) value should not be re-peat.

Inputxml :

        <Main>
 <Request>
    <TypeInd>I</TypeInd> 
    <CustAcctID>505665599</CustAcctID> 
     <ServiceOrderID>1452653</ServiceOrderID> 
  </Request>
  <Request>
  <TypeInd>O</TypeInd> 
  <CustAcctID>2011395</CustAcctID> 
   <ServiceOrderID>1452652</ServiceOrderID> 
       </Request>
     <Request>
    <TypeInd>I</TypeInd> 
   <CustAcctID>505665599</CustAcctID> 
    <ServiceOrderID>1452653</ServiceOrderID> 
       </Request>
       </Main> 

Output XML :

 <Main>
      <Request>
         <TypeInd>I</TypeInd> 
         <CustAcctID>505665599</CustAcctID> 
        <ServiceOrderID>1452653</ServiceOrderID> 
   </Request>
 <Request>
       <TypeInd>O</TypeInd> 
       <CustAcctID>2011395</CustAcctID> 
         <ServiceOrderID>1452652</ServiceOrderID> 
  </Request>

Here is XSLt i tried but didn't work like it retrun duplicate request node

   <?xml version="1.0" encoding="UTF-8"?>
       <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:fo="http://www.w3.org/1999/XSL/Format">
      <xsl:template match="@*|node()">
     <xsl:copy>
         <xsl:apply-templates select="@*|node()" />
      </xsl:copy>
     </xsl:template>
     <xsl:template match="/">
     <xsl:if test="not(following::Request[CustAcctID=current()])">
     <xsl:copy>
       <xsl:apply-templates select="@*|node()" />
      </xsl:copy>
    </xsl:if>
 </xsl:template>
 </xsl:stylesheet>

回答1:

You can remove the duplicate with following XSLT:

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>
<xsl:strip-space elements="*"/>
<xsl:template match="@*|node()">
<xsl:copy>
     <xsl:apply-templates select="@*|node()" />
</xsl:copy>
</xsl:template>
<xsl:template match="Request[CustAcctID = following::Request/CustAcctID]"/>  
</xsl:stylesheet>

Output XML:

<?xml version="1.0" encoding="UTF-8"?>
<Main>
  <Request>
    <TypeInd>O</TypeInd> 
    <CustAcctID>2011395</CustAcctID> 
    <ServiceOrderID>1452652</ServiceOrderID> 
  </Request>
  <Request>
    <TypeInd>I</TypeInd> 
    <CustAcctID>505665599</CustAcctID> 
    <ServiceOrderID>1452653</ServiceOrderID> 
  </Request>
</Main>

The template matching all Request nodes where the CustAcctID matches the CustAcctID of the following Request will not produce any output for the matching Request, so the duplicates will not be written.

Update for the advice in the comment by michael.hor257k: Another approach is to use Muenchian grouping:

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" version="1.0" encoding="UTF-8" indent="yes"/>
<xsl:strip-space elements="*"/>
<xsl:key name="x" match="ServiceOrderID" use="." />
<xsl:template match="@*|node()">
<xsl:copy>
   <xsl:apply-templates select="@*|node()" />
</xsl:copy>
</xsl:template> 
<xsl:template match="Request">
<xsl:for-each select=".">
  <xsl:if test="generate-id(ServiceOrderID) =
                generate-id(key('x', ServiceOrderID)[1])">
     <xsl:copy>
        <xsl:apply-templates select="@*|node()" />
     </xsl:copy>
  </xsl:if>
</xsl:for-each>
</xsl:template>
</xsl:stylesheet>

which produces the same output XML but can be more efficient as you'll find described in detail in the article by Jeni Tennison http://www.jenitennison.com/xslt/grouping/muenchian.xml that michael.hor257k already recommended.

As additional reference for XSLT grouping you can have a look at http://www.dpawson.co.uk/xsl/sect2/N4486.html