Selecting a node based on the value of a node in another document

Question

If I had a lookup table in XML like this:

<lookup>
    <element key='abc'>Hello</element>
</lookup>

And another XML file like this:

<root>
    <child key='abc'>Goodbye</child>
</root>

And I do this XSL transformation after loading the first file into a variable:

<xsl:variable name="myvar" select="document('lookupfile.xml')/lookup" />
<xsl:value-of select="$myvar/element[@key=/root/child/@key]" />

What I want is the value 'Hello' to come up, but instead I get nothing. Am I not allowed to compare the value of two nodes directly? Every example I see always compares [@key='hardCodedValue'] and never to the value of another node.

If I hardcode the value like so: select="$myvar/element[@key='abc'] it returns 'Hello'. If I directly output the value of the root/child key with select="/root/child/@key" I get the correct value 'abc'. It's just when I try to do the comparison above that it returns nothing.

Please post a complete example that can be used to reproduce the issue. Your code is taken out of context - and context is crucial in XPath/XSLT. — michael.hor257k
– michael.hor257k, Commented Nov 5, 2014 at 18:48

JLRishe · Accepted Answer · 2014-11-05 18:49:03Z

1

Inside the predicate, the context is the element element of the lookupfile.xml document, so /root/child/@key is going to be evaluated within that document.

You can either do this, with current():

<xsl:variable name="myvar" select="document('lookupfile.xml')/lookup" />
<xsl:value-of select="$myvar/element[@key = current()/root/child/@key]" />

or store the value in a variable and use that:

<xsl:variable name="myvar" select="document('lookupfile.xml')/lookup" />
<xsl:variable name="mykey" select="/root/child/@key" />
<xsl:value-of select="$myvar/element[@key = $mykey]" />

answered Nov 5, 2014 at 18:49

JLRishe

102k19 gold badges138 silver badges171 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Jimmy James Over a year ago

Using current() solved the problem in my simple test example! It didn't work in my actual XML document, though dumping the value of the '/root/child/@key' equivalent in a variable did. I'll try and figure out why current() isn't working in my real file, but I think I'm on the right track. Thanks!

Collectives™ on Stack Overflow

Selecting a node based on the value of a node in another document

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related