How about:
order(x, runif(length(x)))
Patrick Burns
patr...@burns-stat.com
+44 (0)20 8525 0696
http://www.burns-stat.com
(home of "The R Inferno" and "A Guide for the Unwilling S User")
Rainer M Krug wrote:
Sorry for replying to my own post, but I found a solution. Still, a
more elegant solution would be preferred.
On Thu, Jun 4, 2009 at 12:02 PM, Rainer M Krug <r.m.k...@gmail.com> wrote:
Hi
I want to use order() to get the order of a vector.
But I would need a different behavior when ties occur: similar to the
parameter ties.method = "random" in the rank() function, I would need
to randomise the ties. Is this possible?
The solution is to randomize the vector before submitting to order():
x <- rep(1:10, 2)
iS <- sample( length(x) )
o <- order( x[iS], na.last=NA, decreasing=TRUE)
o
[1] 8 16 12 17 2 9 7 15 10 11 4 14 3 5 13 20 1 6 18 19
x[iS][o]
[1] 10 10 9 9 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1
iS <- sample( length(x) )
o <- order( x[iS], na.last=NA, decreasing=TRUE)
o
[1] 14 19 13 20 2 18 3 10 1 15 4 9 11 12 6 7 8 16 5 17
x[iS][o]
[1] 10 10 9 9 8 8 7 7 6 6 5 5 4 4 3 3 2 2 1 1
Thanks
Rainer
Example:
x <- rep(1:10, 2)
order(x)
[1] 1 11 2 12 3 13 4 14 5 15 6 16 7 17 8 18 9 19 10 20
order(x)
[1] 1 11 2 12 3 13 4 14 5 15 6 16 7 17 8 18 9 19 10 20
## I would need different "order" for the ties, as below in rank() example:
rank(x, ties.method="random")
[1] 1 4 6 7 10 12 13 15 18 19 2 3 5 8 9 11 14 16 17 20
rank(x, ties.method="random")
[1] 2 4 5 7 9 12 14 15 18 19 1 3 6 8 10 11 13 16 17 20
Thanks
Rainer
--
Rainer M. Krug, Centre of Excellence for Invasion Biology,
Stellenbosch University, South Africa
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