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, -- Jose Claudio Faria Brasil/Bahia/UESC/DCET Estatistica Experimental/Prof. Adjunto mails: joseclaudio.faria at terra.com.br jc_faria at uesc.br jc_faria at uol.com.br tel: 73-3634.2779
On 7/9/05, Jose Claudio Faria <joseclaudio.faria at terra.com.br> 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 | > |--------------------| >Try this and see ?lower.tri A <- matrix(0,5,5) A[lower.tri(A)] <- 1:10 B <- A + t(A)
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,