Re: More XPath 1.0 Expression help

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Subject: Re: More XPath 1.0 Expression help
From: Todd Ditchendorf <itod@xxxxxxxxx>
Date: Wed, 19 Jul 2006 14:52:26 -0700

Thanks Mike and Spencer, that definitely got me going in the right direction!

However, I don't think I have XSLT grouping available to me in this case... let me explain.

This XPath is to be used in a Schematron <sch:asstert> test attribute. I am using the XSLT ref impl of Schematron 1.5 running against libxslt witch is limited to XSLT 1.0 and XPath 1.0. I don't think i can access exslt from the schematron schema ,so exslt is out.

Also, I'm assuming that I cannot access XSLT grouping mechanisms from within the schematron schema, so that, unfortunately, is out too. : ( Please correct me if I'm wrong there.

So here's what i've got so far:

	<sch:pattern name="Report Duplicate Keys">
		<sch:rule context="/plist/dict/key">
			<sch:assert test="count(../key[.=current()]) = 1">
					Duplicate '<sch:value-of select="."/>' key exists
					<sch:value-of select="count(../key[.=current()])"/> times.
					Keys should be unique.</sch:assert>
		</sch:rule>
	</sch:pattern>

So I have access to the XSLT current() func but no XSLT grouping features AFAIK. This rule gets the job of detecting duplicate keys done... unfortunately it also raises n errors for n duplicate keys rather than just one error for n duplicate keys. That's certainly not a show-stopper... but it would be nice to fix.

Any ideas?

The O(n^2) complexity doesn't bother me in this instance as perf is not a prime concern here and the data set is very small anyway.

Here's what the actual input looks like... it's an Apple plist:

<plist>
<dict>
<key>Key1</key>
<value/>
<key>Key2</key>
<value/>
<key>Key3</key>
<value/>
<key>Key1</key>
<value/>
</dict>
</plist>

Todd

On Jul 19, 2006, at 2:22 PM, Michael Kay wrote:

Take a look at http://www.jenitennison.com/xslt/grouping

Most of the techniques for grouping are at the XSLT level, but you can use the basic

key[not(. = preceding-sibling::key)]

if you don't mind O(n^2) complexity.

This detects the distinct values: leave out the not() and you have an
expression that detects the duplicates.

Michael Kay
http://www.saxonica.com/


-----Original Message-----
From: Todd Ditchendorf [mailto:itod@xxxxxxxxx]
Sent: 19 July 2006 22:18
To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
Subject:  More XPath 1.0 Expression help


I need some help constructing an XPath to detect nodes
containing duplicate string-values. I am currently restricted
to XPath 1.0 syntax , so no access to distinct-values() or
exslt unfortunately.

I have a document like this:

<dict>
<key>Key1</key>
<value/>
<key>Key2</key>
<value/>
<key>Key3</key>
<value/>
<key>Key1</key>
<value/>
</dict>

How do I create an XPath 1.0 expression to detect the <key>
elements with duplicate string-values?

Thanks!


Todd Ditchendorf
Software Engineer
itod@xxxxxxxxx

Current Thread
More XPath 1.0 Expression help Todd Ditchendorf - 19 Jul 2006 21:18:03 -0000 Michael Kay - 19 Jul 2006 21:23:11 -0000 Spencer Tickner - 19 Jul 2006 21:45:38 -0000 Todd Ditchendorf - 19 Jul 2006 21:52:43 -0000 <= Michael Kay - 19 Jul 2006 22:10:31 -0000 Wendell Piez - 19 Jul 2006 22:25:56 -0000 Todd Ditchendorf - 19 Jul 2006 22:38:45 -0000

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Re: More XPath 1.0 Expression, Spencer Tickner	Thread	RE: More XPath 1.0 Expression, Michael Kay
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