R devel - Dec 2003 - matrix coercion, logical -> character

Anyone know whether this is intentional, and by which rationale?
(R-devel on RedHat, but hardly new)

> l <- data.frame(a=rpois(10,1)>0,b=rpois(10,1)>0)
> apply(l,1,which)
Error in FUN(newX[, i], ...) : argument to "which" is not
logical
> lapply(l,mode)
$a
[1] "logical"

$b
[1] "logical"
> mode(as.matrix(l))
[1] "character"


-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard@biostat.ku.dk)             FAX: (+45) 35327907

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.

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.


> 
> 
> > l <- data.frame(a=rpois(10,1)>0,b=rpois(10,1)>0)
> > apply(l,1,which)
> Error in FUN(newX[, i], ...) : argument to "which" is not logical
> > lapply(l,mode)
> $a
> [1] "logical"
> 
> $b
> [1] "logical"
> 
> > mode(as.matrix(l))
> [1] "character"
> 
> 
> 
-- 
Brian D. Ripley,                  ripley@stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
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