[R] generate matrices
David Winsemius
dwinsemius at comcast.net
Thu Feb 9 17:59:24 CET 2012
On Feb 9, 2012, at 8:38 AM, Blaz Simcic wrote:
> Dear all,
> I would like to generate 500 matrices of 20 numbers from
> standard normal distribution with names x1,x2,x3,….x500.
> I tried with loop for, but I don’t know how to name matices :
> for (i in 1:500) {
> x[[i]] <- matrix(rnorm(20), 4) }
> Any suggestion?
Don't do it that way. Create an array-object instead.
> x <- array(NA, dim=c(4,5,500) )
> x[] <- rnorm(4*5*500)
> str(x)
num [1:4, 1:5, 1:500] -0.721 0.896 -1.432 0.386 -1.111 ...
> dimnames(x)[[3]] <- paste("x", 1:500, sep="")
> str(x)
num [1:4, 1:5, 1:500] -0.721 0.896 -1.432 0.386 -1.111 ...
- attr(*, "dimnames")=List of 3
..$ : NULL
..$ : NULL
..$ : chr [1:500] "x1" "x2" "x3" "x4" ...
--
David Winsemius, MD
West Hartford, CT
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