[R] Converting dataframe to matrix
Philipp Pagel
p.pagel at wzw.tum.de
Fri Oct 16 10:51:45 CEST 2009
On Fri, Oct 16, 2009 at 01:33:14AM -0700, Noah Silverman wrote:
> Hi,
>
> I'm experimenting with a few learners that require a matrix as their
> input. (Currently svmpath, vbmp, etc.)
>
> I currently have a dataframe with 50 columns and 20,000 rows.
>
> I tried using:
>
> x <- as.matrix(my_data.frame)
>
> If I then as, "is.matrix(x)", I get TRUE.
>
> However everywhere I've tried to use the matrix returns errors.
Without more information I can't even start to guess what is going
wrong. Please give a short, reproducible example of what you did and
what errors you encountered.
as.matrix() should suffice for creating a matrix from a data.frame :
> foo <- data.frame(1:4, 4:1, sqrt(1:4), log(4:1))
> foo
X1.4 X4.1 sqrt.1.4. log.4.1.
1 1 4 1.000000 1.3862944
2 2 3 1.414214 1.0986123
3 3 2 1.732051 0.6931472
4 4 1 2.000000 0.0000000
> det(foo)
Error in UseMethod("determinant") :
no applicable method for "determinant"
> det(as.matrix(foo))
[1] -0.1092489
So probably your problem is somewhere else.
cu
Philipp
--
Dr. Philipp Pagel
Lehrstuhl für Genomorientierte Bioinformatik
Technische Universität München
Wissenschaftszentrum Weihenstephan
Freising, Germany
http://webclu.bio.wzw.tum.de/~pagel/
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