Output only Duplicates in the final Text Output - xslt

Question

I am trying to output only one line per unique value in my final text output after running an XML through an XSL stylesheet. In my research, I came upon the distinct-values function, but I'm unable to execute it the way that I want.
Here is my XML:
<Library>
<Book>
<Code>1</Code>
<Title>MANAGEMENT</Title>
</Book>
<Book>
<Code>1</Code>
<Title>MANAGEMENT</Title>
</Book>
<Book>
<Code>1</Code>
<Title>MANAGEMENT</Title>
</Book>
<Book>
<Code>1</Code>
<Title>MANAGEMENT</Title>
</Book>
<Book>
<Code>1</Code>
<Title>MANAGEMENT</Title>
</Book>
<Book>
<Code>10</Code>
<Title>MECHANICAL</Title>
</Book>
<Book>
<Code>106</Code>
<Title>TRANSPORTATION</Title>
</Book>
</Library>
And here is my current XSL (incorrect):
<xsl:template match="Book">
<xsl:value-of select="this:fixedOutput(Code)" />
<xsl:value-of select="this:fixedOutput(Title)" />
<xsl:value-of select="$linefeed" />
</xsl:template>
My output right now is:
1|MANAGEMENT| 1|MANAGEMENT| 1|MANAGEMENT| 1|MANAGEMENT| 1|MANAGEMENT|
10|MECHANICAL| 106|TRANSPORTATION|
But I want it to be this:
1|MANAGEMENT| 10|MECHANICAL| 106|TRANSPORTATION|
I'm not sure how to use the syntax of distinct values to get to where I need.

Answer 1

An XSLT 1.0 solution that uses key and the generate-id() function (Muenchian grouping) to get distinct values :
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:key name="bookCode" match="/Library/Book/Code" use="." />
<xsl:template match="/">
<xsl:for-each select="/Library/Book/Code[generate-id()
= generate-id(key('bookCode',.)[1])]">
<xsl:value-of select="this:fixedOutput(.)" />
<xsl:value-of select="this:fixedOutput(../Title)" />
<xsl:value-of select="$linefeed" />
</xsl:for-each>
</xsl:template>
An XSLT 2.0 solution which uses xsl:for-each-group as #michael.hor257k said :
<?xml version="1.0" encoding="UTF-8" ?>
<xsl:transform xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
version="2.0" xmlns:xs="http://www.w3.org/2001/XMLSchema"
exclude-result-prefixes="xs">
<xsl:template match="node()|#*">
<xsl:copy>
<xsl:apply-templates select="node()|#*" />
</xsl:copy>
</xsl:template>
<xsl:template match="Library">
<xsl:for-each-group select="Book" group-by="concat(Code,Title)">
<xsl:apply-templates select="." />
</xsl:for-each-group>
</xsl:template>
<xsl:template match="Book">
<xsl:value-of select="this:fixedOutput(Code)" />
<xsl:value-of select="this:fixedOutput(Title)" />
<xsl:value-of select="$linefeed" />
</xsl:template>
Note: As this:fixedOutput in your code doen't refer any namespace it has been used as it is.
Refer this: http://xsltransform.net/3MP2uBE