XSLT: remove all but the first occurrence of a given node - xslt

Question

I have XML something like this:
<MyXml>
<RandomNode1>
<TheNode>
<a/>
<b/>
<c/>
</TheNode>
</RandomeNode1>
<RandomNode2>
</RandomNode2>
<RandomNode3>
<RandomNode4>
<TheNode>
<a/>
<b/>
<c/>
</TheNode>
</RandomNode4>
</RandomNode3>
</MyXml>
Where <TheNode> appears throughout the XML but not at the same level, often deep within other nodes. What I need to do is eliminate all occurrences of <TheNode> EXCEPT the first. The rest are redundant and taking up space. What would be the XSL that could do this?
I have something like this:
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" indent="yes"/>
<xsl:template match="node() | #*">
<xsl:copy>
<xsl:apply-templates select="node() | #*" />
</xsl:copy>
</xsl:template>
<xsl:template match="//TheNode[position()!=1]">
</xsl:template>
</xsl:stylesheet>
But that is not correct. Any suggestions?

Answer 1

<?xml version="1.0" encoding="ISO-8859-1"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" indent="yes"/>
<xsl:template match="node() | #*">
<xsl:copy>
<xsl:apply-templates select="node() | #*"/>
</xsl:copy>
</xsl:template>
<xsl:template match="TheNode[preceding::TheNode]"/>
</xsl:stylesheet>

Answer 2

//TheNode[position()!=1] does not work because here, position() is relative to the parent context of each <TheNode>. It would select all <TheNode>s which are not first within their respective parent.
But you were on the right track. What you meant was:
(//TheNode)[position()!=1]
Note the parentheses - they cause the predicate to be applied to the entire selected node-set, instead of to each node individually.
Unfortunately, even though this is valid XPath expression, it is not valid as a match pattern. A match pattern must be meaningful (applicable) to an individual node, it cannot be a select expression.
So #Alohci's solution,
//TheNode[preceding::TheNode]
is the correct way to express what you want.

Answer 3

Other approach for the pattern would be:
<xsl:template match="TheNode[generate-id()
!= generate-id(/descendant::TheNode[1)]"/>
Note: It's more likely that an absolute expression gets optimizated inteads of a relative expression like preceding::TheNode