RE: question with using Muenchian/xsl:key (Re: sort/group/co

Thanks for the tip, you are making a very good point, I will sure add it to
my code.

Thanks again,

Xiaocun Xu
xxu@xxxxxxxxxxxxxxxxxx



> -----Original Message-----
> From: G. Ken Holman [mailto:gkholman@xxxxxxxxxxxxxxxxxxxx]
> Sent: Wednesday, November 15, 2000 5:27 AM
> To: xsl-list@xxxxxxxxxxxxxxxx
> Subject: Re: question with using Muenchian/xsl:key (Re: 
> sort/group/count
> probl em)
> 
> 
> At 00/11/11 23:30 +0000, David Carlisle wrote:
> > >
> > > key('items-by-itemid', @itemid) returns all items with 
> the same @itemid in
> > > the entire XML document.  I just want all items with the 
> same @itemid in
> > >  each of the itemlist element, how can I do that?
> >
> >don't you just want to replace
> >
> ><xsl:key name="items-by-itemid" match="item" use="@itemid"/>
> >
> >by something like
> >
> ><xsl:key name="items-by-itemid" match="item"
> >use="concat(generate-id(..),@itemid)"
> >/>
> >
> >so that your key values are all specific to a given itemlist.
> >
> >Not that I've tried it....
> 
> This is precisely the basis of a section of my instructor-led 
> tutorial and 
> exercise to do sub-tree subsetting of the xsl:key facility, 
> but with one 
> addition.
> 
> I teach use="concat(generate-id(subtree-root-expression),' 
> ',value-expression)" because of the remote (but possible) 
> synthesis of 
> ambiguous use values.  If the generated id of two nodes were "N1" and 
> "N12", and the corresponding value expressions were 
> coincidentally "23" and 
> "3", then the values would be "N123" and "N123".
> 
> Since the generated id is always a name token, and the name 
> token can never 
> have a space character, the space is an effective delimiter 
> to guarantee 
> uniqueness.
> 
> I hope this helps.
> 
> ..................... Ken


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