Date: Thu, 6 Jun 1996 10:41:35 +1200 From: Ross Ihaka <ihaka@stat.auckland.ac.nz> Message-Id: <199606052241.KAA06969@stat.auckland.ac.nz> To: r-testers@stat.math.ethz.ch Subject: Re: R-alpha: batch mode and interactions In-Reply-To: <9606042333.AA23240@attunga.stats.adelaide.edu.au> <199606042316.LAA03075@stat.auckland.ac.nz> Bill Venables writes: > Rather than use a "." for interactions would you consider using a > ":" to reflect the (low level) operator that creates them? I'm a little worried that a:b is not a valid name, but I must admit to not knowing whether this matters or not. It would be a trivial change (as would leaving out the "." a la S). > Of course even this does not go far enough. There are two types of > "interaction" between factors, the "A:B" type and the "B %in% A" > type which are equivalent in abstract terms to "B + A:B". I think > labelling is potentially very important in this area but doing it > justice is going to generate labels far too long. You can't win. This is something I have neglected, but think it will not be too hard to change the terms function so that this will work. It would mean that y~a*b/c would produce the terms a, b ,a:b, c%in%(a*b). I think I will squeeze the spaces from around the %in% to save space. By the by. Our Mac programmer is back and so we are back on track for ports to the 68k and PPC Macs. Ross =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- r-testers mailing list -- To (un)subscribe, send subscribe or unsubscribe (in the "body", not the subject !) To: r-testers-request@stat.math.ethz.ch =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-