Subject: RE: [xsl] xpath // query From: "Michael Kay" <michael.h.kay@xxxxxxxxxxxx> Date: Wed, 24 Apr 2002 14:32:47 +0100 |
> For example, is: > > select="A//C" > > any different to: > > select="A//B//C" > > when I know that <B> is *guranteed* to be there (both select the same > nodes). By adding the test for <B>, will it make the > selection any faster? > No, it's likely to make it slower. The second expression will search all the descendants of A looking for a B, and all the descendants of each B looking for a C. So the descendants of a B will actually be visited (and usually rejected) twice. Of course the usual caveats apply - some processors may be doing optimizations that I'm not aware of. Michael Kay Software AG home: Michael.H.Kay@xxxxxxxxxxxx work: Michael.Kay@xxxxxxxxxxxxxx XSL-List info and archive: http://www.mulberrytech.com/xsl/xsl-list
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