On Thu, 2010-03-18 at 00:57 +0000, ted.hard...@manchester.ac.uk wrote: > On 17-Mar-10 23:32:41, Ross Boylan wrote: > > While browsing some code I discovered a call to lm that used > > a formula y ~ X - 1, where X was a matrix. > > > > Looking through the documentation of formula, lm, model.matrix > > and maybe some others I couldn't find this useage (R 2.10.1). > > Is it anything I can count on in future versions? Is there > > documentation I've overlooked? > > > > For the curious: model.frame on the above equation returns a > > data.frame with 2 columns. The second "column" is the whole X > > matrix. model.matrix on that object returns the expected matrix, > > with the transition from the odd model.frame to the regular > > matrix happening in an .Internal call. > > > > Thanks. > > Ross > > > > P.S. I would appreciate cc's, since mail problems are preventing > > me from seeing list mail. > > Hmmm ... I'm not sure what is the problem with what you describe. There is no problem in the "it doesn't work" sense. There is a problem that it seems undocumented--though the help you quote could rather indirectly be taken as a clue--and thus, possibly, subject to change in later releases.
Ross Boylan ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
