[R] permutates and/or samples a matrix
David Winsemius
dwinsemius at comcast.net
Thu Jan 31 14:44:46 CET 2008
On 31 Jan 2008, you wrote in gmane.comp.lang.r.general:
> Hi,
>
> sample(x) only permutates and/or samples from a vector, which I
> can't use for a matrix. Please help.
You just feed sample(.) a "redimensioned" object. If you need to do it
programmatically just multiply the dimensions of the matrix to create a
length for the working vector.
> xm<-rnorm(25)
> xmtx<-matrix(xm,dim<-c(5,5))
> samp<-sample(as.matrix(xmtx,dim<-c(1,25)))
> samp
#output of 25 numbers elided
> samp<-sample(as.matrix(xmtx,dim<-c(1,25)),10)
> samp
[1] 0.26421745 0.63888288 1.06176705 -1.56074510 -0.72471549 -
0.38743020
[7] -0.68765683 1.18081648 -1.51566762 0.07560708
--
David Winsemius
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