Thursday, March 31, 2011

XSLT - How to select XML Attribute by Attribute?

Hello, this is the structure of my source xml:

<root>
<DataSet Value="A">
<Data Value1="1" Value2="anythingA1" />
<Data Value1="2" Value2="anythingA2" />
<Data Value1="3" Value2="anythingA3" />
<Data Value1="4" Value2="anythingA4" />
<Data Value1="5" Value2="anythingA5" />
</DataSet>
</root>

from which I like to create some variables e.g. from all with Value1="2" and all with Value1="5" should result myVar1 with anythingA2 and myVar2 with anythingA5

My approch looks like this

<xsl:variable name="myVarA" select="/DataSet/Data/[@Value1='2']/@Value2" />

but of course is not working since Value2 is no child of Value1.

thanks for any hints in advance!

From stackoverflow
  • Just remove the slash after Data and prepend the root:

    <xsl:variable name="myVarA" select="/root/DataSet/Data[@Value1='2']/@Value2"/>
    
    Andrew Hare : -1 this does not work without the root node
    phihag : @Andrew Hare: Corrected. Thanks to Quassnoi for elaborating, I lost connection immediately after posting the first revision.
    Jeff Yates : added +1 and sacrificed a goat
    spoulson : +1 and did a little jig
  • There are two problems with your xpath - first you need to remove the child selector from after Data like phihag mentioned. Also you forgot to include root in your xpath. Here is what you want to do:

    select="/root/DataSet/Data[@Value1='2']/@Value2"
    
  • Try this

    xsl:variable name="myVarA" select="//DataSet/Data[@Value1='2']/@Value2" />
    

    The '//' will search for DataSet at any depth

  • sometimes its so easy, thanks a lot!

  • I would do it by creating a variable that points to the nodes that have the proper value in Value1 then referring to t

    <xsl:variable name="myVarANode" select="root//DataSet/Data[@Value1='2']" />
    <xsl:value-of select="$myVarANode/@Value2"/>
    

    Everyone else's answers are right too - more right in fact since I didn't notice the extra slash in your XPATH that would mess things up. Still, this will also work , and might work for different things, so keep this method in your toolbox.

  • Note: using // at the beginning of the xpath is a bit CPU intensitve -- it will search every node for a match. Using a more specific path, such as /root/DataSet will create a faster query.

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