Stephen Cole wrote:
...
I have a vector of 20 values
x <- c(20,18, 45, 16, 47, 47, 15, 26, 14,14,12,16,35,27,18,94,16,26,26,30)
1.
I want to select random pairs from this data set but do it without
replacement exhaustively
matrix(x[sample(1:20,20)],nrow=2)
then step through the columns of the resulting matrix
I know i can select random pairs without replacement using
sample(N,n,replace=F)
However i am wondering if there is any way to get 10 random pairs from this
data set without repeating any of the data points
that is to say if i got a (20, 94) for one pair, i would like to get 9 other
pairs from the data without again getting 20 or 94?
2.
The second thing i would like to do is be able to select all possible pairs
of numbers and calculate each pairs variance.
I think you want to use the combn function, but you are going to get a
lot of pairs...
Jim
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