The following seems to be a contradiction:
df <- data.frame(x=gl(2,1,10)) df[,1]
[1] 1 2 1 2 1 2 1 2 1 2 Levels: 1 2
df[,1,drop=F]
x 1 1 2 2 3 1 4 2 5 1 6 2 7 1 8 2 9 1 10 2
is.factor(df[,1,drop=F])
[1] FALSE
is.factor(df[,1])
[1] TRUE with R1.2.1 both MS Windows and Intel RH5.2 versions. Jim -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- 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 _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._