leaps: regsubsets, formula including interactions
Hi R-list members, Could somebody explain to me the meaning of the '.' in the formula SumTL~. below? I could not find it in the help pages. I'm guessing it is substituted by v1+v2+v3+.. for all independent variables vi. Furthermore, I would like to add interaction effects to the model, is this also possible with the '.'?
library(leaps) d<-regsubsets(SumTL~.,nbest=2,data=dat[,-c(2,9)]) x11() ; par(mfrow=c(1,4)) ; plot(d) ; plot(d,scale="Cp") ;
plot(d,scale="adjr2") ; plot(d,scale="r2") My data 'dat' variable looks like this:
str(dat)
'data.frame': 548 obs. of 9 variables: $ SumTL: int 13500 67800 158000 299000 486000 712000 56100 162000 310000 471000 ... $ SumUL: int 13800 69700 163000 308000 497000 726000 58100 168000 319000 481000 ... $ Ord : int 96 192 288 384 480 576 192 288 384 480 ... $ Incid: int 0 0 0 0 0 0 0 0 0 0 ... $ f1 : int 1 1 1 1 1 1 1 1 1 1 ... $ f2 : int 0 0 0 0 0 0 0 0 0 0 ... $ f3 : int 0 0 0 0 0 0 0 0 0 0 ... $ f4 : int 0 0 0 0 0 0 0 0 0 0 ... $ f5 : int 0 0 0 0 0 0 0 0 0 0 ... Thanks, Jonne.