[R] a silly question on index of a matrix

Simon Blomberg blomsp at ozemail.com.au
Wed Oct 26 04:19:41 CEST 2005


 > ?which
 > X <- matrix(2:10, nrow=3)
 > which(X == 10, arr.ind=TRUE)
      row col
[1,]   3   3

HTH,

simon.

At 11:52 AM 26/10/2005, you wrote:
>Hi netters,
>
>This is probably a silly question,but I can't find the answer after 
>searching the R-help archives online. ok, I have a matrix. I know there is 
>a "10" somewhere in it. Now I want to
>know the index of the element "10" in this matrix. That is, if X[i,j]=10, 
>I want to know
>i and j. Is there a R function to do this? Just like the "find" function 
>in matlab.
>
>Thanks all!
>
>
>
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Simon Blomberg, B.Sc.(Hons.), Ph.D, M.App.Stat.
Centre for Resource and Environmental Studies
The Australian National University
Canberra ACT 0200
Australia
T: +61 2 6125 7800 email: Simon.Blomberg_at_anu.edu.au
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