On 10-Aug-07 18:05:50, Lanre Okusanya wrote:
> Hello all,
>
> I am working with a 1000x1000 matrix, and I would like to return a
> 1000x1000 matrix that tells me which value in the matrix is greater
> than a theshold value (1 or 0 indicator).
> i have tried
> mat2<-as.matrix(as.numeric(mat1>0.25))
> but that returns a 1:100000 matrix.
> I have also tried for loops, but they are grossly inefficient.
>
> THanks for all your help in advance.
>
> Lanre
Simple-minded, but:
> S<-matrix(rnorm(25),nrow=5)
> S
[,1] [,2] [,3] [,4] [,5]
[1,] -0.9283624 -0.44418487 1.1174555 1.9040999 -0.4675796
[2,] 0.2658770 -0.28492642 -1.2271013 -0.5713291 1.8036235
[3,] 0.7010885 -0.42972262 0.7576021 0.3407972 -1.0628487
[4,] -0.2003087 0.87006841 0.6233792 -0.9974902 -0.9104270
[5,] 0.2729014 0.09781886 -1.0004486 1.5987385 -0.4747125
> T<-0*S
> T[S>0.25] <- 1+0*S[S>0.25]
> T
[,1] [,2] [,3] [,4] [,5]
[1,] 0 0 1 1 0
[2,] 1 0 0 0 1
[3,] 1 0 1 1 0
[4,] 0 1 1 0 0
[5,] 1 0 0 1 0
Does this work OK for your big matrix?
HTH
Ted.
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E-Mail: (Ted Harding) <[EMAIL PROTECTED]>
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Date: 10-Aug-07 Time: 19:50:37
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