Hi,
Look at ?combn
t(combn(Vector, 2))
gives:
[,1] [,2]
[1,] "a" "b"
[2,] "a" "c"
[3,] "b" "c"
No idea how it is speed-wise.
HTH,
Josh
On Fri, Jul 22, 2011 at 10:09 AM, Megh Dal <megh700...@yahoo.com> wrote:
> Let say, I have a character vector of arbitrary length:
>
> Vector <- c("a", "b", "c")
>
> Using that vector I would like to create a matrix (with number of columns as
> 2) with all pairwise combinations of those elements, like:
>
> Vector <- c("a", "b", "c")
> Mat <- rbind(c("a", "b"), c("a", "c"), c("b", "c")); Mat # number of
> rows will obviously be n(n-1)/2
> [,1] [,2]
> [1,] "a" "b"
> [2,] "a" "c"
> [3,] "b" "c"
>
>
> Order must be kept same as c("c", "a") or c("c", "b") would not be allowed.
> Additionally, actually I have a very big initial character vector therefore I
> need to maintain speed as well.
>
> I would be really grateful if somebody guide me how to do that
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
--
Joshua Wiley
Ph.D. Student, Health Psychology
University of California, Los Angeles
https://joshuawiley.com/
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