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Editorial Team
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Asked: 2026-05-23T13:25:15+00:00

I didn’t found an explicit way to select all nodes that exist between two

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I didn’t found an explicit way to select all nodes that exist between two anchors (<a></a> tag pair) in an HTML file.

The first anchor has the following format:

<a href="file://START..."></a>

Second anchor:

<a href="file://END..."></a>

I’ve verified that both can be selected using starts-with (note that I’m using HTML Agility Pack):

HtmlNode n0 = html.DocumentNode.SelectSingleNode("//a[starts-with(@href,'file://START')]"));
HtmlNode n1 = html.DocumentNode.SelectSingleNode("//a[starts-with(@href,'file://END')]"));

With this in mind, and with my amateurish XPath skills, I wrote the following expression to get all tags between the two anchors:

html.DocumentNode.SelectNodes("//*[not(following-sibling::a[starts-with(@href,'file://START0')]) and not (preceding-sibling::a[starts-with(@href,'file://END0')])]");

This seems to work, but selects all HTML document!

I need to, for example for the following HTML fragment:

<html>
...

<a href="file://START0"></a>
<p>First nodes</p>
<p>First nodes
    <span>X</span>
</p>
<p>First nodes</p>
<a href="file://END0"></a>

...
</html>

remove both anchors, the three P (including of course the inner SPAN).

Any way to do this?

I don’t know if XPath 2.0 offers better ways to achieve this.

*EDIT (special case!) *

I should also handle the case where:

“Select tags between X and X’, where X is <p><a href="file://..."></a></p>“

So instead of:

<a href="file://START..."></a>
<!-- xhtml to be extracted -->
<a href="file://END..."></a>

I should handle also:

<p>
  <a href="file://START..."></a>
</p>
<!-- xhtml to be extracted -->

<p>
  <a href="file://END..."></a>
</p>

Thank you very much, again.

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1 Answer

  1. Editorial Team

    Use this XPath 1.0 expression:

    //a[starts-with(@href,'file://START')]/following-sibling::node()
     [count(.| //a[starts-with(@href,'file://END')]/preceding-sibling::node())
     =
      count(//a[starts-with(@href,'file://END')]/preceding-sibling::node())
     ]

    Or, use this XPath 2.0 expression:

        //a[starts-with(@href,'file://START')]/following-sibling::node()
  intersect
    //a[starts-with(@href,'file://END')]/preceding-sibling::node()

    The XPath 2.0 expression uses the XPath 2.0 intersect operator.

    The XPath 1.0 expression uses the Kayessian (after @Michael Kay) formula for the intersectioon of two node-sets:

    $ns1[count(.|$ns2) = count($ns2)]

    Verification with XSLT:

    This XSLT 1.0 transformation:

    <xsl:stylesheet version="1.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
 <xsl:output omit-xml-declaration="yes" indent="yes"/>
 <xsl:strip-space elements="*"/>

 <xsl:template match="/">
  <xsl:copy-of select=
  "    //a[starts-with(@href,'file://START')]/following-sibling::node()
         [count(.| //a[starts-with(@href,'file://END')]/preceding-sibling::node())
         =
          count(//a[starts-with(@href,'file://END')]/preceding-sibling::node())
         ]
  "/>
 </xsl:template>
</xsl:stylesheet>

    when applied on the provided XML document:

    <html>...
    <a href="file://START0"></a>
    <p>First nodes</p>
    <p>First nodes    
        <span>X</span>
    </p>
    <p>First nodes</p>
    <a href="file://END0"></a>...
</html>

    produces the wanted, correct result:

    <p>First nodes</p>
<p>First nodes    
        <span>X</span>
</p>
<p>First nodes</p>

    This XSLT 2.0 transformation:

    <xsl:stylesheet version="2.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
 <xsl:output omit-xml-declaration="yes" indent="yes"/>
 <xsl:strip-space elements="*"/>

 <xsl:template match="/">
  <xsl:copy-of select=
  " //a[starts-with(@href,'file://START')]/following-sibling::node()
   intersect
    //a[starts-with(@href,'file://END')]/preceding-sibling::node()
  "/>
 </xsl:template>
</xsl:stylesheet>

    when applied on the same XML document (above) again produces exactly the wanted result.

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