[R] random sampling inside a dataset

[Berend Hasselman]

On 13-09-2012, at 10:42, Gian Maria Niccolò Benucci wrote:

> Hi all,
> 
> I am wondering if do exist a function in R that allow me to sample or
> choose randomly the rows (i.e., samples) inside a given matrix.

Use sample.
Like this for example

A <- matrix(runif(8*4), nrow=8)
A

select.row <- sample(1:nrow(A), size= nrow(A)/3, replace=FALSE)
select.row
A[select.row,]

Berend