Oh my goodness David! Don't forget that matrices are just vectors in
column major order.
> m/rep(v,e=2)
[,1] [,2] [,3]
[1,] 2 2 2
[2,] 1 1 1
(the generalization is obvious)
should be far more efficient and simpler than running apply loops.
-- Cheers,
Bert
Bert Gunter
Genentech Nonclinical Biostatistics
(650) 467-7374
"Data is not information. Information is not knowledge. And knowledge
is certainly not wisdom."
H. Gilbert Welch
On Wed, May 14, 2014 at 7:59 AM, David L Carlson <dcarl...@tamu.edu> wrote:
> You don't need do.call:
>
>> t(t(m)/v)
> [,1] [,2] [,3]
> [1,] 2 2 2
> [2,] 1 1 1
>
>> t(apply(m, 1, function(x) x/v))
> [,1] [,2] [,3]
> [1,] 2 2 2
> [2,] 1 1 1
>
> -------------------------------------
> David L Carlson
> Department of Anthropology
> Texas A&M University
> College Station, TX 77840-4352
>
>
> -----Original Message-----
> From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On
> Behalf Of carol white
> Sent: Wednesday, May 14, 2014 9:52 AM
> To: r-h...@stat.math.ethz.ch
> Subject: [R] matrix column division by vector
>
> Hi,
> What is the elegant script to divide the columns of a matrix by the
> respective position of a vector elements?
>
> m=rbind(c(6,4,2),c(3,2,1))
>
> v= c(3,2,1)
>
> res= 6/3 4/2 2/1
> 3/3 2/2 1/1
>
>
> this is correct
> mat2 = NULL
>
> for (i in 1: ncol(m))
>
> mat2 = cbind(mat2, m[,i]/ v[i])
>
>
> but how to do more compact and elegant with for ex do.call?
>
> Many thanks
>
> Carol
> [[alternative HTML version deleted]]
>
> ______________________________________________
> 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.
