[Rd] rank (PR#7850)

[ripley at stats.ox.ac.uk]

You don't understand what rank() does: it is not the same as sort.list but 
rather the reverse (in the absence of ties).

>  x<- c(2,-5,1,3);x
[1]  2 -5  1  3
> y <- x
> y[rank(x)] <- x
> y
[1] -5  1  2  3

The ranks are the numbers in the ordering, and -5 is the smallest and so 
has rank 1, and so on.

Not a bug at all.

On Wed, 11 May 2005 stella.david at math.uni-augsburg.de wrote:

> Full_Name: Stella David
> Version: 2.1.0
> OS: mingw32
> Submission from: (NULL) (137.250.161.136)
>
>
> It seems that rank doesn't work right on vectors containing negative values.
> If the negative value is the first component or there are only two components,
> it works, but if the negative value is somewhere in the middle there's a
> problem.
>
> Here are my examples:
>> # wrong:
>> x<- c(2,-5,1,3);x
> [1]  2 -5  1  3
>> rank(x)
> [1] 3 1 2 4
>> x[rank(x)]
> [1]  1  2 -5  3
>>
>> # but this works:
>> y<- c(-5,2,1,3);y
> [1] -5  2  1  3
>> rank(y)
> [1] 1 3 2 4
>> y[rank(y)]
> [1] -5  1  2  3
>> z <- c(3,-5);z
> [1]  3 -5
>> rank(z)
> [1] 2 1
>> z[rank(z)]
> [1] -5  3
>>
>> version
>         _
> platform i386-pc-mingw32
> arch     i386
> os       mingw32
> system   i386, mingw32
> status
> major    2
> minor    1.0
> year     2005
> month    04
> day      18
> language R
>
> Stella David
>
> ______________________________________________
> R-devel at stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>
>

-- 
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)
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