[R] Standard deviation for each element in a set of matrices

[Gray Calhoun]

Hi Muhammad,
  Load the data from all of the files into an array (probably using a
for loop), then call apply on the resulting array: ie

## replace the first line with code to load your data
> rr <- array(c(rep(1:3,3), rep(4:6,3), rep(7:9,3)), c(3,3,3))
> apply(rr, c(1,2), sd)
     [,1] [,2] [,3]
[1,]    3    3    3
[2,]    3    3    3
[3,]    3    3    3

--Gray

On Fri, Dec 4, 2009 at 11:56 AM, Muhammad Rahiz
<muhammad.rahiz at ouce.ox.ac.uk> wrote:
> Hello R-users,
>
> I would like to know how to find the standard deviation for each element in
> a set of matrices.
>
> Given the following files,
>
>   File1    File2    File3
>   1 1 1   4 4 4   7 7 7
>   2 2 2   5 5 5   8 8 8
>   3 3 3   6 6 6   9 9 9
>
> I want to calculate the standard deviation for every cell in the file (I'm
> using gridded data). The desired output is
>
>   Output
>   3 3 3
>   3 3 3
>   3 3 3
>
>
> Thanks.
>
> Muhammad
>
> --
> Muhammad Rahiz  |  Doctoral Student in Regional Climate Modeling
>
> Climate Research Laboratory, School of Geography & the Environment
> Oxford University Centre for the Environment
> South Parks Road, Oxford, OX1 3QY, United Kingdom Tel: +44 (0)1865-285194
>  Mobile: +44 (0)7854-625974
> Email: muhammad.rahiz at ouce.ox.ac.uk
>
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-- 
Gray Calhoun

Assistant Professor of Economics
Iowa State University