Question

I have the following XSLT variable:

<xsl:variable name="superid" select="/contentdata/id"/>

Furthermore, I have a node with subnodes:

<nodes>
    <node name="foo" id="bar" />
    <node name="john" id="doe" />
    <node name="jane" id="tarzan" />
</nodes>

Now, I’d like to check if a node with an id attribute that equals superid exists.

I’ve tried the following (which obviously doesn’t work):

<xsl:if test="/nodes/node[@id = $superid]">Yes, Sir!</xsl:if>

Answer 1

Use:

boolean(/nodes/node/@id = $superid)

Here is a complete transformation, showing this in action:

<xsl:stylesheet version="1.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
 <xsl:output method="text"/>
 <xsl:strip-space elements="*"/>

 <xsl:variable name="vDoe" select="'doe'"/>
 <xsl:variable name="vXyz" select="'xyz'"/>

 <xsl:template match="/">
     id attribute with value "doe' exists: <xsl:text/>
     <xsl:value-of select="boolean(/nodes/node/@id = $vDoe)"/>
==========
     id attribute with value "xyz' exists: <xsl:text/>
     <xsl:value-of select="boolean(/nodes/node/@id = $vXyz)"/>
 </xsl:template>
</xsl:stylesheet>

when this transformation is applied on the provided XML document:

<nodes>
    <node name="foo" id="bar" />
    <node name="john" id="doe" />
    <node name="jane" id="tarzan" />
</nodes>

the wanted, correct result is produced:

     id attribute with value "doe' exists: true
==========
     id attribute with value "xyz' exists: false