On Mon, 8 Dec 2003, Patrick Burns wrote: > It seems another reason to make the change would be the > ability to work around the following feature: > > > lmat <- as.matrix(data.frame(a=c(FALSE, TRUE))) > > lmat > a > 1 "FALSE" > 2 " TRUE" > > mode(lmat) <- "logical" > > > > lmat > a > 1 FALSE > 2 NA > > Numeric, character and logical were mentioned. Complex data > frames coerce to complex matrices already.
(Yes, complex is numeric for this purpose. I had checked that out.) > Apropos of this, it would be good to put a See Also "complex" > in the "numeric" help file and vice versa. > > Patrick Burns > > Burns Statistics > [EMAIL PROTECTED] > +44 (0)20 8525 0696 > http://www.burns-stat.com > (home of S Poetry and "A Guide for the Unwilling S User") > > Peter Dalgaard wrote: > > >Prof Brian Ripley <[EMAIL PROTECTED]> writes: > > > > > > > >>On 8 Dec 2003, Peter Dalgaard wrote: > >> > >> > >> > >>>Anyone know whether this is intentional, and by which rationale? > >>>(R-devel on RedHat, but hardly new) > >>> > >>> > >>It is documented: > >> > >> 'as.matrix' is a generic function. The method for data frames will > >> convert any non-numeric column into a character vector using > >> 'format' and so return a character matrix. > >> > >> > > > >and for apply: > > > > If 'X' is not an array but has a dimension attribute, 'apply' > > attempts to coerce it to an array via 'as.matrix' if it is > > two-dimensional (e.g., data frames) or via 'as.array'. > > > >explains why apply(...., which) got in trouble > > > > > > > >>Remember than not some long ago you could not have logical columns in data > >>frames: they were coerced to factors. > >> > >>It would be easy to change to allow numeric, logical or character > >>matrices. > >> > >> > > > >Yes. That was the direction in which I was hinting. It does seem a bit > >like a leftover, and applying which() over a set of logical > >columns is not unlikely to be useful in practice. > > > > > > > > > > -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-devel
