Douglas Bates <[EMAIL PROTECTED]> writes: > > x <- c(1:10) #data to be broken up into dummy variables > > v <- c(3,5,7) #breakpoints > > p = 1 #drop this column to avoid dummy variable trap > > > > How can I get a matrix "y" that has the associated dummy variables for > > columns? > > Don't. > > Consider why you want the dummy variables. You probably want to use > them in the specification of a statistical model and R's model > specification language automatically expands a factor variable into a > set of contrasts.
... However, if you insist on seeing what goes on behind the scenes, try x <- c(1:10) vv <- c(-Inf,v,Inf) f <- cut(x,vv) model.matrix(~f) model.matrix(~f)[,-1] model.matrix(~f-1) -- O__ ---- Peter Dalgaard Blegdamsvej 3 c/ /'_ --- Dept. of Biostatistics 2200 Cph. N (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907 ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help
