RE: Standard XPath expression for the intersection of two no

 Subject: RE: Standard XPath expression for the intersection of two node se ts (Was: RE: How can I test if an node included in a nodeset) From: Ed Blachman Date: Fri, 4 Aug 2000 14:22:33 -0400
```I think the answer here is that in some sense you're both right, but Oliver
is closer to standard usage:

http://mathworld.wolfram.com/SetDifference.html defines "set difference" in
a manner that matches Oliver's expression; it references in addition
something the "symmetric difference" of two sets
(http://mathworld.wolfram.com/SymmetricDifference.html) which matches Ken's
expression.

-- ed

> -----Original Message-----
> From: G. Ken Holman [mailto:gkholman@xxxxxxxxxxxxxxxxxxxx]
> Sent: Friday, August 04, 2000 12:31 PM
> To: xsl-list@xxxxxxxxxxxxxxxx
>
> At 00/08/04 10:59 +0200, Oliver Becker wrote:
> >I don't know if anybody has mentioned this before:
> >
> >If we add a single exclamation mark
> >    \$nodes1[count(.|\$nodes2)!=count(\$nodes2)]
> >it will become the difference of the two node-sets \$nodes1
> and \$nodes2.
>
> I disagree, though I thought the same at first when saw
> Mike's great post
> ... what you have will be those in \$nodes1 not in \$nodes2,
> but not those in
> \$nodes2 not in \$nodes1.
>
> I figured you would need:
>
>     (   \$ns1[count(.|\$ns2)!=count(\$ns2)]
>       | \$ns2[count(.|\$ns1)!=count(\$ns1)] )
>
> to get the true difference as I understand it, that being all
> nodes in both sets not in the other set.  I have an example below.

XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list

```

PURCHASE STYLUS STUDIO ONLINE TODAY!

Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced!