[R] rank(x,y)?
Peter Dalgaard
p.dalgaard at biostat.ku.dk
Wed Jun 21 20:07:31 CEST 2006
Duncan Murdoch <murdoch at stats.uwo.ca> writes:
> Suppose I have two columns, x,y. I can use order(x,y) to calculate a
> permutation that puts them into increasing order of x,
> with ties broken by y.
>
> I'd like instead to calculate the rank of each pair under the same
> ordering, but the rank() function doesn't take multiple values
> as input. Is there a simple way to get what I want?
>
> E.g.
>
> > x <- c(1,2,3,4,1,2,3,4)
> > y <- c(1,2,3,1,2,3,1,2)
> > rank(x+y/10)
> [1] 1 3 6 7 2 4 5 8
>
> gives me the answer I want, but only because I know the range of y and
> the size of gaps in the x values. What do I do in general?
Still not quite general, but in the absence of ties:
> z[order(x,y)]<-1:8
> z
[1] 1 3 6 7 2 4 5 8
--
O__ ---- Peter Dalgaard Øster Farimagsgade 5, Entr.B
c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907
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