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    copied!<p><strong>This solution is a little bit simpler, more efficient and at the same time more general</strong> than the one presented by Richard:</p> <p><strong>This transformation</strong>:</p> <pre><code>&lt;xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"&gt; &lt;!-- --&gt; &lt;xsl:key name="kFileByVal" match="File" use="." /&gt; &lt;!-- --&gt; &lt;xsl:key name="kDescByFile" match="Description" use="../File"/&gt; &lt;!-- --&gt; &lt;xsl:template match="/*"&gt; &lt;html&gt; &lt;body&gt; &lt;xsl:for-each select= "*/File[generate-id() = generate-id(key('kFileByVal',.)[1])]"&gt; &lt;h1&gt;&lt;xsl:value-of select="."/&gt;&lt;/h1&gt; &lt;xsl:for-each select="key('kDescByFile', .)"&gt; &lt;p&gt;&lt;xsl:value-of select="."/&gt;&lt;/p&gt; &lt;/xsl:for-each&gt; &lt;/xsl:for-each&gt; &lt;/body&gt; &lt;/html&gt; &lt;/xsl:template&gt; &lt;/xsl:stylesheet&gt; </code></pre> <p><strong>when applied to the provided XML document</strong>:</p> <pre><code>&lt;Problems&gt; &lt;Problem&gt; &lt;File&gt;file1&lt;/File&gt; &lt;Description&gt;desc1&lt;/Description&gt; &lt;/Problem&gt; &lt;Problem&gt; &lt;File&gt;file1&lt;/File&gt; &lt;Description&gt;desc2&lt;/Description&gt; &lt;/Problem&gt; &lt;Problem&gt; &lt;File&gt;file2&lt;/File&gt; &lt;Description&gt;desc1&lt;/Description&gt; &lt;/Problem&gt; &lt;/Problems&gt; </code></pre> <p><strong>Produces the wanted result</strong>:</p> <pre><code>&lt;html&gt; &lt;body&gt; &lt;h1&gt;file1&lt;/h1&gt; &lt;p&gt;desc1&lt;/p&gt; &lt;p&gt;desc2&lt;/p&gt; &lt;h1&gt;file2&lt;/h1&gt; &lt;p&gt;desc1&lt;/p&gt; &lt;/body&gt; &lt;/html&gt; </code></pre> <p><strong>Do note</strong> the simple match pattern of the first <a href="http://www.w3.org/TR/xslt#key" rel="noreferrer"><strong><code>&lt;xsl:key&gt;</code></strong></a> and how, using a second <code>&lt;xsl:key&gt;</code>, we locate all "<code>Description</code>" elements that are siblings of a "<code>File</code>" element that has a given value.</p> <p>We could have used more templates instead of <a href="http://www.w3.org/TR/xslt#for-each" rel="noreferrer"><strong><code>&lt;xsl:for-each&gt;</code></strong></a> pull-processing, however this is a quite simple case and the solution really benefits from shorter, more compact and more readable code.</p> <p><strong>Also note, that in <a href="http://www.w3.org/TR/xslt20/" rel="noreferrer">XSLT 2.0</a> one will typically use the <a href="http://www.w3.org/TR/xslt20/#xsl-for-each-group" rel="noreferrer"><code>&lt;xsl:for-each-group&gt;</code></a> instruction</strong> instead of the <a href="http://dpawson.co.uk/xsl/sect2/N4486.html#d6060e85" rel="noreferrer"><strong>Muenchian method</strong></a>.</p>
 

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