Re: xxRe: efficient use of key element and function
Hi David, in my original post I wrote (sorry for the typo "xxRe: ..."): >Given a rather long list of unique names I want to know for a >certain name if it is on that list. The stylesheet below does >this, but is this the best (most efficient) solution? In the most >common case around 95% of the names will be found. > >In the real stylesheet the names represent files and are used >to avoid a file-not-found for doc(). They are retrieved by means >of collection(). The stylesheet below is the original one, except for the key element. Instead of <xsl:key name="find" match="*" use="."/> it is now <xsl:key name="find" match="name" use="text()"/> Is this the best (most efficient) solution? <?xml version="1.0" encoding="UTF-8" ?> <xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"> <xsl:key name="find" match="name" use="text()"/> <xsl:template match="/"> <xsl:variable name="Index-alt"> <doc> <name> <xsl:text>schmid_hans</xsl:text> </name> <name> <xsl:text>prunauer_katharina</xsl:text> </name> <name> <xsl:text>senkenwald_wolfgang</xsl:text> </name> </doc> </xsl:variable> <xsl:value-of select="empty(key('find', 'prunauer_regina', $Index-alt))"/> <xsl:value-of select="empty(key('find', 'strada_jacopo', $Index-alt))"/> </xsl:template> </xsl:stylesheet> On 9/7/05, David Carlisle <davidc@xxxxxxxxx> wrote: > > > I was thinking the use attribute only comes into play _after_ a match > > was found and in some way can be viewed as a return value (per node) > > no you have that backwards, the use attribute specifies the allowe > _arguments_ to the key function, the match attribute specifies teh > returned value. > > key('x',...) (in xslt1) is a function from strings to node sets > > key('x','"foo") returns a set of nodes with key "foo". > > The way this is function is defined is that the set of nodes returned is > the set of nodes that match the match attribute, and have a use > attribute that evaluates to "foo". > > > > If might be better to match on text() than on * > >For my test-case it should be the same. > > They will only be the same if your input document only has one element > (and no comments). > > If you have > > <xsl:key match="*" use="."/> > > Then the key for the top level element will be all the character data in > the document, concatenated. The system will then have to ake a hash > table entry using that large string as label. > > key('x',string(/*)) would then return this element, but you would be a > lot more efficient just to use > /* > without using keys at all. > > David > > ________________________________________________________________________ > This e-mail has been scanned for all viruses by Star. The > service is powered by MessageLabs. For more information on a proactive > anti-virus service working around the clock, around the globe, visit: > http://www.star.net.uk > ________________________________________________________________________
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