How do I use XPath to count the number of nodes with a certain attribute

Question

I can't seem to get an XPath expression to work for my scenario. I want to find all the "Device" nodes that have the type "EndDevice". I'm able to count all the "Device" nodes, and I'm also able to find all "Device" nodes with the "EndDevice" attribute. However, I can't seem to combine them!

count(//Device) //works
//Device[@xsi:type='EndDevice'] //works
count(//Device[@xsi:type='EndDevice']) //doesn't work

If it matters, I'm using XPathBuilder.

Solution 1

I reproduced it using XPathBuilder 2.0.0.4. However the XPath expression works and evaluates correctly in an online evaluator I tried (http://www.whitebeam.org/library/guide/TechNotes/xpathtestbed.rhtm).

EDIT: Also tried with latest version of Altova XMLspy

input:

<?xml version="1.0"?>
<asdf xmlns:xsi="n/a">
    <Device xsi:type='EndDevice'/>
    <Device xsi:type='EndDevice'/>
    <Device xsi:type='EndDevice'/>
    <Device xsi:type='EndDevice'/>
</asdf>

xslt:

<?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" xmlns:xsi="n/a">
    <xsl:output indent="yes"/>
    <xsl:template match="*">
        <output>
            <xsl:value-of select="count(//Device[@xsi:type = 'EndDevice'])"/>
        </output>
    </xsl:template>
</xsl:stylesheet>

output:

<?xml version="1.0" encoding="UTF-8"?>
<output xmlns:fo="http://www.w3.org/1999/XSL/Format" xmlns:xsi="n/a">4</output>

I think it's XPathBuilder thats doing something wrong.

Solution 2

Using the above xml saved into a test.xml and using the tool http://kernowforsaxon.sourceforge.net/

declare namespace xsi="n/a"; 
count(doc('test.xml')//Device[@xsi:type = "EndDevice"])

Produces the right output.