Row-binding factor variables looses the ordered attribute.
On Thu, 14 Mar 2002, Patrick Lindsey wrote:
[...]
The covariate name "I(cov != 2)" is now (in R1.4.1) appended by the value TRUE. I think that this must come from "model.matrix" which must be transforming a boolean vector into a factor variable (which I would guess is not really necessary as this is just a binary vector). This change of behavior is not really a problem in itself (if it only concerns the behavior of "model.matrix") but quite unexpected.
It is in the NEWS file ....
Brian D. Ripley, ripley@stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272860 (secr) Oxford OX1 3TG, UK Fax: +44 1865 272595 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-devel-request@stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._