On 08-Dec-05 Ales Ziberna wrote:
> Dear useRs!
>
> I would like to list all possible samples of size n form a
> population of size N. Obviously, N must be small (up to 20??)
> for this to be possible.
>
> For example, let say that N = 3 and n = 2. Therefore, we can
> say we have units 1, 2 and 3. I believe all possible samples
> are : {1,2},{2,3} and {1,3}.
>
> I would like to emphasize that I am not looking for the number
> of different samples, but a list of all possible samples.
Install package "combinat" and use the function 'combn' therein:
> library(combinat)
> ?combn
> combn((1:3),2)
[,1] [,2] [,3]
[1,] 1 1 2
[2,] 2 3 3
> combn((1:5),2)
[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
[1,] 1 1 1 1 2 2 2 3 3 4
[2,] 2 3 4 5 3 4 5 4 5 5
> combn((1:5),3)
[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
[1,] 1 1 1 1 1 1 2 2 2 3
[2,] 2 2 2 3 3 4 3 3 4 4
[3,] 3 4 5 4 5 5 4 5 5 5
and so on ...
Best wishes,
Ted.
--------------------------------------------------------------------
E-Mail: (Ted Harding) <[EMAIL PROTECTED]>
Fax-to-email: +44 (0)870 094 0861
Date: 08-Dec-05 Time: 15:07:37
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