Hi, A recent thread provided a (working) construct for lm: lm(as.matrix(freeny[ix]) ~., freeny[-ix]) Can someone explain what is meant by the formula in that expression, that is, what does "mymatrix~." do? I couldn't find any such example in the lm() or formula() help pages. thanks Carl
See the Details section of ?lm where its all discussed. On Sun, Nov 29, 2009 at 11:46 AM, Carl Witthoft <carl@witthoft.com> wrote:> Hi, > A recent thread provided a (working) construct for lm: > > lm(as.matrix(freeny[ix]) ~., freeny[-ix]) > > > Can someone explain what is meant by the formula in that expression, > that is, what does "mymatrix~." do? I couldn't find any such example in > the lm() or formula() help pages. > > thanks > Carl > > ______________________________________________ > 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. >[[alternative HTML version deleted]]
The help page for lm says:
"If ?response? is a matrix a linear model is fitted separately by
least-squares to each column of the matrix."
-Ista
On Sun, Nov 29, 2009 at 11:46 AM, Carl Witthoft <carl at witthoft.com>
wrote:> Hi,
> A recent thread provided a (working) construct for lm:
>
> lm(as.matrix(freeny[ix]) ~., freeny[-ix])
>
>
> Can someone explain what is meant by the formula in that expression,
> that is, ?what does "mymatrix~." ?do? ?I couldn't find any
such example in
> the lm() or formula() help pages.
>
> thanks
> Carl
>
> ______________________________________________
> R-help at 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.
>
--
Ista Zahn
Graduate student
University of Rochester
Department of Clinical and Social Psychology
http://yourpsyche.org
On Nov 29, 2009, at 11:46 AM, Carl Witthoft wrote:> Hi, > A recent thread provided a (working) construct for lm: > > lm(as.matrix(freeny[ix]) ~., freeny[-ix]) > > > Can someone explain what is meant by the formula in that expression, > that is, what does "mymatrix~." do?It doesn't say my matrix, it says as.matrix, and that is because freeny[iz] is most probably a dataframe. The lm function is capable of doing manova when given a matrix on the LHS of the formula: http://www.r-project.org/doc/Rnews/Rnews_2007-2.pdf see page 2 and onward of Dalgaard's article. Toward the end of the Details section of formula help page (easily accessed with a click from the lm help page) you will find the explanation for the "~."> I couldn't find any such example in the lm() or formula() help pages. > > thanks > Carl > > ______________________________________________ > R-help at 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.David Winsemius, MD Heritage Laboratories West Hartford, CT
As others helpfully pointed out, the meaning of "." in a formula is provided in the Details section of ?formula. (But NOT in ?lm) Ista Zahn wrote:> The help page for lm says: > > "If ?response? is a matrix a linear model is fitted separately by > least-squares to each column of the matrix." > > -Ista > > On Sun, Nov 29, 2009 at 11:46 AM, Carl Witthoft <carl at witthoft.com> wrote: >> Hi, >> A recent thread provided a (working) construct for lm: >> >> lm(as.matrix(freeny[ix]) ~., freeny[-ix]) >> >> >> Can someone explain what is meant by the formula in that expression, >> that is, what does "mymatrix~." do? I couldn't find any such example in >> the lm() or formula() help pages. >> >> thanks >> Carl >> >> ______________________________________________ >> R-help at 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. >> > > >