Subject: RE: XPath/XSLT 2.0: What is the most efficient way to find if a sequence is empty?
From: "Michael Kay" <mhk@xxxxxxxxx>
Date: Sun, 5 Oct 2003 15:46:18 +0100
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There are two complementary functions empty($seq) and exists($seq).
I would expect any decent optimizer to generate exactly the same code
for these as for count($x)=0 - but I guess there are processors out
there that don't have decent optimizers.
Michael Kay
> -----Original Message-----
> From: owner-xsl-list@xxxxxxxxxxxxxxxxxxxxxx
> [mailto:owner-xsl-list@xxxxxxxxxxxxxxxxxxxxxx] On Behalf Of
> Dimitre Novatchev
> Sent: 04 October 2003 22:00
> To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
> Subject: XPath/XSLT 2.0: What is the most efficient way
> to find if a sequence is empty?
>
>
> In XSLT/XPath 1.0 one would use:
>
> not($node-set)
>
> to find if $node-set is the empty node-set.
>
> However, the same test on a sequence in XPath 2.0:
>
> not($seq)
>
> may return 'true' for a non-empty sequence -- e.g. for:
> ( false() )
>
> or for
>
> (0)
>
> My question: Is there a more efficient test for an empty sequence than
>
> count($seq) = 0
>
>
>
>
> =====
> Cheers,
>
> Dimitre Novatchev.
> http://fxsl.sourceforge.net/ -- the home of FXSL
>
>
>
>
> XSL-List info and archive: http://www.mulberrytech.com/xsl/xsl-list
>
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