R help - Oct 2005 - a silly question on index of a matrix

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!

> ?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
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