On Mon, 2008-06-16 at 15:35 -0500, [EMAIL PROTECTED] wrote:
> hi: you can do below but i don't know if it's worth it ?
>
> newx <- data.matrix(data.frame(x))
> print(newx)
That doesn't work Mark:
> str(data.frame(x))
'data.frame': 2 obs. of 2 variables:
$ X1: Factor w/ 2 levels "1","2": 1 2
$ X2: Factor w/ 2 levels "3","4": 1 2
> data.matrix(data.frame(x))
X1 X2
[1,] 1 1
[2,] 2 2
Which is as per documentation - the data.frame() coerces to factors and
data.matrix represents factor by their internal values.
One "solution" might be to save the dims and then reapply:
> mat
[,1] [,2]
[1,] "1" "3"
[2,] "2" "4"
> dims <- dim(mat)
> mat2 <- as.numeric(mat)
> dim(mat) <- dims
> mat2
[,1] [,2]
[1,] 1 3
[2,] 2 4
You could wrap this in a function:
asMatrix <- function(x, ...) {
dims <- dim(x)
x <- as.double(x)
dim(x) <- dims
return(x)
}
It would be logical to define a method for as.double for matrix objects.
However objects of class "matrix" are not objects in the sense of
isObject() and hence method dispatch will not work in this case.
HTH
G
>
>
> On Mon, Jun 16, 2008 at 4:22 PM, Alberto Monteiro wrote:
>
> > Why does as.numeric convert matrices and arrays to vectors?
> >
> > as.numeric(matrix(c("1", "2", "3", "4"), 2, 2))
> > [1] 1 2 3 4
> >
> > I could only figure out ugly ways to bypass this, like:
> >
> > x <- matrix(c("1", "2", "3", "4"), 2, 2)
> > array(as.numeric(x), dim = dim(x), dimnames = dimnames(x))
> >
> > Alberto Monteiro
> >
> > ______________________________________________
> > 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.
>
> ______________________________________________
> 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.
--
%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%
Dr. Gavin Simpson [t] +44 (0)20 7679 0522
ECRC, UCL Geography, [f] +44 (0)20 7679 0565
Pearson Building, [e] gavin.simpsonATNOSPAMucl.ac.uk
Gower Street, London [w] http://www.ucl.ac.uk/~ucfagls/
UK. WC1E 6BT. [w] http://www.freshwaters.org.uk
%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%~%
______________________________________________
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.
