Comparing Values

[David]

Hi,

I'm new to XML and XSLT in particular so if this is a stupid question
then I apologise.

I have an XML file which contains a number of occurrences of a
specific element for example

<test>Value1</test>
<test>Value2</test>
etc

Is it possible using XSLT to compare whether an element is the same as
the previous element of the same name (does that make any kind of
sense, what I mean is the first <test> value the same as the next
<test> value, which in the example above would not be the case)?

I'm trying to create a template match which only occurs when the
current occurrence of the node is the same as the previous occurrence
of the node. It's basically so that in the output HTML I can keep the
current table open when the two values match and close it when they
change (to correct some table nesting issues that I seem to have run
up against).

I can only manage it at the moment when I know what the possible
values are in advance which means it isn't much use (the value could
be any combination of up to 6 characters so thats a whole lot of
possible combinations to check for).

Any assistance would be greatly appreciated, or even just to know
whether it's possible or not.

Thanks

 

[David Carlisle]

Is it possible using XSLT to compare whether an element is the same as
the previous element of the same name (does that make any kind of
sense, what I mean is the first <test> value the same as the next
<test> value, which in the example above would not be the case)?

yes that would be
<xsl:if test=".=preceding::test[1]"> ....

however you don't want this

I'm trying to create a template match which only occurs when the
current occurrence of the node is the same as the previous occurrence
of the node. It's basically so that in the output HTML I can keep the
current table open when the two values match and close it when they
change (to correct some table nesting issues that I seem to have run
up against).

Not the XSLT way of thinking of things, you can't "close a table" in some
template on some condition as you are not writing tags such as
"</table>" but creatinga node tree, so you first generate a table node
then populate it with the elements you want, so you need to decide what
they are up front by selecting each group of elements that should end up
in the same table.

This grouping problem isa faq and best answered at Jeni's site

www.jenitennison.com/xslt/grouping

David

 

[David]

Thanks, that FAQ covers it very nicely. A much neater way of doing things.

Is it possible using XSLT to compare whether an element is the same as
the previous element of the same name (does that make any kind of
sense, what I mean is the first <test> value the same as the next
<test> value, which in the example above would not be the case)?

yes that would be
<xsl:if test=".=preceding::test[1]"> ....

however you don't want this

I'm trying to create a template match which only occurs when the
current occurrence of the node is the same as the previous occurrence
of the node. It's basically so that in the output HTML I can keep the
current table open when the two values match and close it when they
change (to correct some table nesting issues that I seem to have run
up against).

Not the XSLT way of thinking of things, you can't "close a table" in some
template on some condition as you are not writing tags such as
"</table>" but creatinga node tree, so you first generate a table node
then populate it with the elements you want, so you need to decide what
they are up front by selecting each group of elements that should end up
in the same table.

This grouping problem isa faq and best answered at Jeni's site

www.jenitennison.com/xslt/grouping

David