Oh, so we can always combine model matrices and formulas in regression in R?
Thanks! On Mon, May 14, 2012 at 2:41 AM, peter dalgaard <pda...@gmail.com> wrote: > > On May 14, 2012, at 02:24 , Luna wrote: > > > Thanks! > > > > Do you think if the correctness of the such results could be generalized > to > > other future cases? > > > If correctly generalized, yes.... > > (Apologies for being slightly facetious; the point is that the properties > you build on are part of the software design for model formulas and model > matrices. They are not fortuitous buglets, so they are not going to go away > unless the actual design is changed.) > > > > > > > > > > > On Sun, May 13, 2012 at 7:10 PM, S Ellison <s.elli...@lgcgroup.com> > wrote: > > > >>> But the line you cited was about "response" being a matrix, which is > not > >> our case. > >> Yes, you're right; I picked the wrong thing to cite. > >> The only documentation I found about lm accepting a matrix in the > >> predictors is a one-line statement in "Introduction to R" which says > "term_i > >> is either > >> > >> a vector or matrix expression, or 1, > >> a factor, or > >> a formula expression consisting of factors, vectors or matrices > >> connected by formula operators. " > >> > >> Not the most informative documentation. But Peter Dalgaard is a most > >> authoritative source! > >> > >>> And also I have checked: > >>> > >>> Any more thoughts? > >> > >> Data frames are odd things; a column need not contain only a vector if > the > >> number of rows is OK. I am half surprised that including a matrix in one > >> works. But the gods of R are powerful and their magic is strong. Here, > >> names(tmp) is showing that the data frame has one element called X (in > >> effect, the whole matrix is regarded as one element of the data frame), > but > >> on display the magic has expanded X to show all the columns of X. > >> > >> This is the main reason I generally keep to simple things in data > frames; > >> complicated things make it less easy to predict behaviour. > >> > >> > >> > >> ******************************************************************* > >> This email and any attachments are confidential. Any u...{{dropped:13}} > > > > ______________________________________________ > > R-help@r-project.org mailing list > > https://stat.ethz.ch/mailman/listinfo/r-help > > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html<http://www.r-project.org/posting-guide.html> > > and provide commented, minimal, self-contained, reproducible code. > > -- > Peter Dalgaard, Professor > Center for Statistics, Copenhagen Business School > Solbjerg Plads 3, 2000 Frederiksberg, Denmark > Phone: (+45)38153501 > Email: pd....@cbs.dk Priv: pda...@gmail.com > > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.