On Wed, Mar 07, 2012 at 08:41:35AM -0800, Oritteropus wrote:
> Hi,
> I need to sample randomly my dataset for 1000 times. The sample need to be
> the 80%. I know how to do that, my problem is that not only I need the 80%,
> but I also need the corresponding 20% each time. Is there any way to do
> that?
Hi.
If you use sample() to get the 80% and store the indices, you
can also get the remaining cases
a <- matrix(1:30, ncol=3)
i <- sample(10, 8)
a[sort(i), ]
[,1] [,2] [,3]
[1,] 1 11 21
[2,] 2 12 22
[3,] 3 13 23
[4,] 4 14 24
[5,] 6 16 26
[6,] 7 17 27
[7,] 8 18 28
[8,] 10 20 30
a[-i, ]
[,1] [,2] [,3]
[1,] 5 15 25
[2,] 9 19 29
Hope this helps.
Petr Savicky.
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