A colleague asked me if there is a way to specify with a ***variable*** (say ``cflag'') whether there is an intercept in a linear model.
She had in mind something like lm(y ~ x - cflag) where cflag could be 0 or 1; if it's 0 an intercept should be fitted, if it's 1 then no intercept. This doesn't work ``of course''. The cflag just gets treated as another predictor and because it is of the wrong length an error is generated. The best I could come up with was lm(as.formula(paste("y ~ x -",cflag))) Which is kludgy. It (of course!) also be done using an if statement. Is there a sexier way? cheers, Rolf Turner ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html