[R] Error in model.frame

[Göran Broström]

On  0, Uwe Ligges <ligges at statistik.uni-dortmund.de> wrote:
> Göran Broström wrote:
> >I recently ran into the following:
> >
> >
> >>x <- c(1,2,4,3)
> >>lm(x ~ 1:length(x))
> >
> >Error in model.frame(formula, rownames, variables, varnames, extras, 
> >extranames,  : variable lengths differ
> >
> >but
> >
> >
> >>lm(x ~ c(1:length(x)))
> >
> >
> >Call:
> >lm(formula = x ~ c(1:length(x)))
> >
> >Coefficients:
> >   (Intercept)  c(1:length(x))  
> >           0.5             0.8  
> >
> >and
> >
> >
> >>identical(1:4, c(1:4))
> >
> >[1] TRUE
> >
> >Should I report this as a bug?
> 
> NO!!!
> The ":" operator is used to model interactions in lm() and friends!

I forgot that! Thanks to all who remembered.

Göran