R help - Dec 2004 - rank in descending order?

Hi,

Is there any simple solution to get ranks in descending order?
Example, 
a <- c(10, 98, 98, 98, 99, 100)
r <- rank(a, ties.method="average")

produces
1 3 3 3 5 6

I would want this instead:
6 5 3 3 3 1

Note that reversing r doesn't work but in small examples.

Thanks,
-Jose

-- 
 
jquesada at andrew.cmu.edu		Research associate
http://lsa.colorado.edu/~quesadaj	Dept. of Social and Decision Sciences
http://www.andrew.cmu.edu/~jquesada	Carnegie Mellon University
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Try this:

r <- sort(rank(a, ties.method="average"), decreasing=T)


Jose Quesada wrote:
>Hi,
>
>Is there any simple solution to get ranks in descending order?
>Example, 
>a <- c(10, 98, 98, 98, 99, 100)
>r <- rank(a, ties.method="average")
>
>produces
>1 3 3 3 5 6
>
>I would want this instead:
>6 5 3 3 3 1
>
>Note that reversing r doesn't work but in small examples.
>
>Thanks,
>-Jose
>
>  
>

On Wed, 1 Dec 2004, Jose Quesada wrote:
> Is there any simple solution to get ranks in descending order?
> Example,
> a <- c(10, 98, 98, 98, 99, 100)
> r <- rank(a, ties.method="average")
>
> produces
> 1 3 3 3 5 6
>
> I would want this instead:
> 6 5 3 3 3 1
What does that correspond to (why are 98 and 99 ranked the same)?  I 
believe you want 6 4 4 4 2 1, which is length(a) + 1 - r, as well as 
rank(-a).

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595