Use backquotes confint(glht(motA,linfct=mcp(A=c("`2` - `1` = 0 "))))
On Fri, Mar 4, 2011 at 2:03 PM, Ulrich Halekoh <ulrich.hale...@agrsci.dk>wrote: > Using a factor with 'number' levels the straightforward > symbolic formulation of a contrast in 'glht' of > the 'multcomp' package fails. > > How can this problem be resolved without having to redefine the factor > levels? > > Example: > #A is a factor with 'number' levels > #B similar factor with 'letter' levels > dat<-data.frame(y=1:4,A=factor(c(1,1,2,2)), > B=factor(c('e','e','f','f')) ) > motA<-lm(y~A,data=dat) > motB<-lm(y~B,data=dat) > library(multcomp) > #does not work > glht(motA,linfct=mcp(A=c("2 - 1 = 0 "))) > > #the error message is > # Error in coefs(ex[[3]]) : > # cannot interpret expression '1' as linear function > > #works > glht(motB,linfct=mcp(B=c("f - e = 0"))) > > regards > > Ulrich Halekoh > Aarhus University > e-mail: ulrich.hale...@agrsci.dk > > I use R.2.12.2, package version of multcomp : 1.2-5 > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html<http://www.r-project.org/posting-guide.html> > and provide commented, minimal, self-contained, reproducible code. > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.