Sampling procedure
On Oct 15, 2009, at 10:19 AM, Marcio Resende wrote:
I would like to divide a vector in 9 groups in a way that each number is present in only one group. In a vector of 783 I would like to divide in 9 different groups of 87 Example <- matrix(c(1:783),ncol = 1)
> Example <- matrix(c(1:783),ncol = 1) > Grp1 <- sample(Example, 87, replace=FALSE) > Grp2 <- sample(Example[-Grp1], 87, replace=FALSE) > Grp3 <- sample(Example[-c(Grp1, Grp2)], 87, replace=FALSE) # lather, rinse , repeat
s1 <- as.matrix(sample(Example,87, re = FALSE)) Example <- Example[-s1] s2 <- as.matrix(sample(Example,87, re = FALSE)) #however I don?t know how to remove the second group from the "Example" to continue sampling.
#Don't mess up the original
There is probably an easy and faster way to do this. Could anybody help me? Thanks
David Winsemius, MD Heritage Laboratories West Hartford, CT