Re: [xsl] counting elements with values that match other element values

[Wendell Piez <wapiez@xxxxxxxxxxxxxxxx>]

Sean,

It is tempting to try running your code and knowing for sure, but 
even without doing that, insofar as I understand your requirements 
you are almost there. (I can't say for sure because I'm not sure I 
understand your requirements fully. For example, what should happen 
if you have c elements with the same value inside the same cSet?)

But a performant version of this would probably use keys to speed up 
the lookup. Doing it using brute-force XPath, like this, is going to 
bog down on sizable documents.

Since it doesn't sound like this is super-critical, maybe I'll leave 
it at that -- if you can get the key() arrow into your XSLT quiver, 
you'll be doing great.

Cheers,
Wendell

At 07:28 AM 5/18/2006, you wrote:

>     I step away from xpath and xslt for long stretches, and when I 
> come back, parts of the big picture are a little fuzzy.  My sense 
> is that for the problem below, I need to loop; the test can't be 
> done in a single XSLT1.0 statement.
>    I have a set of elements ("t") with children under them 
> ("t/cSet/c").  I'm looking for children that occur twice.  I'd like 
> get a nice 1.0 nodeset, which is the practical reason for trying to 
> shoehorn the task into a single statement.
>    The xslt and xml are below.  I used command-line saxon for debugging.
>    The expression for the element "Find_Cs_In_Ts" is what I'd like 
> to either get working, or get an official confirmation that the 
> task is impossible.  In the real implementation the "> 0" would 
> be " = 2", and the answer would be "3, 5, and 7", which are the 
> numbers that occurs twice in the set.  The other elements are just 
> me playing around with similar constructions that return related data.
>    In SQL, this would be something like
>                            select * from ccc where (select count 
> (*) from T/cSet as TC  where tc.c = ccc.c ) >0
>
>    Any explanation for what the right syntax is, or, conceptually, 
> why the idea doesn't fit in with xslt1.0 would be greatly 
> appreciated.  I've got looping code for the task almost 
> implemented, so, mostly I'm asking for how the parser is reading 
> the expression I wrote, and how far away is what I wrote from what 
> I really wanted?
>    Another approach might be to use the parent axis to walk back up 
> and then over to other T elements to find the related data.
>
> thanks for any suggestions,
>
>
> ======================
> <?xml version="1.0" encoding="UTF-8"?>
> <xsl:stylesheet version="1.0" 
> xmlns:xsl="http://www.w3.org/1999/XSL/Transform"; 
> xmlns:xs="http://www.w3.org/2001/XMLSchema";>
> <xsl:output method="html"/>
> <xsl:template match="/">
>
>    <xsl:call-template name="make-Choices">
>     </xsl:call-template>
>
> </xsl:template>
> <xsl:template name = "make-Choices">
> <xsl:variable  name = "output"  >
>       <xsl:element name="root">
>
>       <xsl:element name = "ccc"><xsl:copy-of select="root/ccc/*"/> 
> </xsl:element>
>    <xsl:element name = "Find_Cs_In_Ts"><xsl:copy-of select="
>        //root/ccc/c[ count(  //root/t[  h =1  and  . =   cSet/c    ]
> ) &gt; 0     ] "/> </xsl:element>
>
>    <xsl:element name = "Count7s_In_TH"><xsl:copy-of select="
>          count(  //root/t[  h =1  and    cSet/c  = 7   ]   )   "/> 
> </xsl:element>
>       <xsl:element name = "Cs_In_Ts"><xsl:copy-of select="
>        //root/ccc/c[  . =  //root/t[  h =1    ]/cSet/c   ]      "/> 
> </xsl:element>
>
>       <xsl:element name = "Count_TCs_In_C"><xsl:copy-of 
> select="count( root/t[h =1]/cSet/c[. =  //root/ccc/c]  ) "/> </xsl:element>
>  </xsl:element>
> </xsl:variable>
>
>  <xsl:copy-of select="$output"/>
> </xsl:template>
>
> </xsl:stylesheet>
>
> ============
> <?xml version="1.0"?>
> <?xml-stylesheet type="text/xsl" href="ukbSmall.xslt"?>
> <root>
>   <ccc>
>
> <c>1</c><c>2</c><c>3</c><c>4</c><c>5</c><c>6</c><c>7</c><c>8</c><c>9</c>
>   </ccc>
>   <t>
>      <h>1</h><v>3</v>
>      <cSet><c>3</c><c>5</c><c>8</c></cSet>
>   </t>
>   <t>
>      <h>1</h><v>4</v>
>      <cSet><c>3</c><c>5</c></cSet>
>   </t>
>   <t>
>      <h>1</h><v>7</v>
>      <cSet><c>7</c><c>8</c></cSet>
>   </t>
>   <t>
>      <h>1</h><v>9</v>
>      <cSet><c>7</c><c>8</c></cSet>
>   </t>
> </root>


======================================================================
Wendell Piez                            mailto:wapiez@xxxxxxxxxxxxxxxx
Mulberry Technologies, Inc.                http://www.mulberrytech.com
17 West Jefferson Street                    Direct Phone: 301/315-9635
Suite 207                                          Phone: 301/315-9631
Rockville, MD  20850                                 Fax: 301/315-8285
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