[R] Help to make a specific matrix
Adaikalavan Ramasamy
ramasamy at cancer.org.uk
Sun Jul 10 14:36:37 CEST 2005
In addition to Gabor's solution, you might be interested in the
combinations function from the gtools package.
library(gtools)
combinations(5,2)
[,1] [,2]
[1,] 1 2
[2,] 1 3
[3,] 1 4
[4,] 1 5
[5,] 2 3
[6,] 2 4
[7,] 2 5
[8,] 3 4
[9,] 3 5
[10,] 4 5
On Sat, 2005-07-09 at 21:42 -0300, Jose Claudio Faria wrote:
> Dear R users,
>
> The solution is probably simple but I need someone to point me to it.
> How can I to generate a matrix from a numeric sequence of 1:10 like 'A' or 'B'
> below:
>
> A)
> |--------------------|
> | 1 2 3 4 5 |
> |--------------------|
> | 1 | 0 |
> | 2 | 1 0 |
> | 3 | 2 5 0 |
> | 4 | 3 6 8 0 |
> | 5 | 4 7 9 10 0 |
> |--------------------|
>
> B)
> |--------------------|
> | 1 2 3 4 5 |
> |--------------------|
> | 1 | 0 1 2 3 4 |
> | 2 | 1 0 5 6 7 |
> | 3 | 2 5 0 8 9 |
> | 4 | 3 6 8 0 10 |
> | 5 | 4 7 9 10 0 |
> |--------------------|
>
> This question is related with the possible combinations of five objects two the
> two, i.e, C(5,2).
>
> Any help would be greatly appreciated.
>
> Regards,
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