Note that the formula uptake ~. will do the same thing so its not clear how useful this facility really is.
On 7/16/07, Ted Harding <[EMAIL PROTECTED]> wrote: > On 16-Jul-07 14:16:10, Gabor Grothendieck wrote: > > Following up on your comments it seems formula.data.frame just creates > > a formula whose lhs is the first column name and whose rhs is made up > > of the remaining column names. It ignores the "formula" attribute. > > > > In fact, CO2 does have a formula attribute but its not extracted by > > formula.data.frame: > > > >> [EMAIL PROTECTED] > > uptake ~ conc | Plant > >> formula(CO2) > > Plant ~ Type + Treatment + conc + uptake > > Indeed! And, following up yet again on my own follow-up comment: > > library(combinat) > > for(j in (1:4)){ > for(i in combn((1:4),j,simplify=FALSE)){ > print(formula(CO2[,c(5,i)])) > } > } > uptake ~ Plant > uptake ~ Type > uptake ~ Treatment > uptake ~ conc > uptake ~ Plant + Type > uptake ~ Plant + Treatment > uptake ~ Plant + conc > uptake ~ Type + Treatment > uptake ~ Type + conc > uptake ~ Treatment + conc > uptake ~ Plant + Type + Treatment > uptake ~ Plant + Type + conc > uptake ~ Plant + Treatment + conc > uptake ~ Type + Treatment + conc > uptake ~ Plant + Type + Treatment + conc > > opening the door to automated fitting of all possible models > (without interactions)! > > Now if only I could find out how to do the interactions as well, > I would never need to think again! > > best wishes, > Ted. > > -------------------------------------------------------------------- > E-Mail: (Ted Harding) <[EMAIL PROTECTED]> > Fax-to-email: +44 (0)870 094 0861 > Date: 16-Jul-07 Time: 15:40:36 > ------------------------------ XFMail ------------------------------ > ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel