Hello!
If I read ?subset, the workings of the argument drop (to me) seem to imply equivalence of A and B (R 1.9.0):
#A dd <- data.frame(rt=rnorm(10), c=factor(gl(2,5))) dd <- subset(dd, c==1) dd$c <- dd$c[, drop=TRUE] table(dd$c)
1
5
#B dd <- data.frame(rt=rnorm(10), c=factor(gl(2,5))) dd <- subset(dd, c==1, drop=TRUE) table(dd$c)
1 2 5 0
So to lose the second level of dd$c, in method B I still need to 'dd$c <- dd$c[, drop=TRUE]', while the manual seems to imply that with the drop argument to subset() this would not be necessary.
Could you comment?
kind regards, Paul
-- Paul Lemmens NICI, University of Nijmegen ASCII Ribbon Campaign /"\ Montessorilaan 3 (B.01.05) Against HTML Mail \ / NL-6525 HR Nijmegen X The Netherlands / \ Phonenumber +31-24-3612648 Fax +31-24-3616066
______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
