R help - Apr 2005 - finding cols and rows in a matrix

Hi
Ive got big matrixes with just few non missing data, and
would like to use or do a funtion to find the index of the row and col of one 
specified value. For example I just have one "1" value in the matrix,
and one
"2" value in the same matrix.

Has anyone an idea about how to extract the rowindex and colindex of the
"1"
value or the "2"?

Thanks

check this:

mat <- matrix(rnorm(5*5), 5, 5)
mat[1, 3] <- 1; mat[4, 2] <- 2
####
which(mat==1, TRUE)
which(mat==2, TRUE)


Best,
Dimitris

----
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/16/336899
Fax: +32/16/337015
Web: http://www.med.kuleuven.ac.be/biostat/
     http://www.student.kuleuven.ac.be/~m0390867/dimitris.htm


----- Original Message ----- 
From: "javier garcia" <rn001 at cebas.csic.es>
To: <r-help at stat.math.ethz.ch>
Sent: Thursday, April 28, 2005 12:55 PM
Subject: [R] finding cols and rows in a matrix

> Hi
> Ive got big matrixes with just few non missing data, and
> would like to use or do a funtion to find the index of the row and 
> col of one
> specified value. For example I just have one "1" value in the 
> matrix, and one
> "2" value in the same matrix.
>
> Has anyone an idea about how to extract the rowindex and colindex of 
> the "1"
> value or the "2"?
>
> Thanks
>
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