[R] Re: [S] Different behaviour of unique(), R vs. Splus.

[Prof Brian Ripley]

On Tue, 29 Jun 2004, Liaw, Andy wrote:

> The source of the incompatibility:
> 
> In S-PLUS 6.2:
> 
> > methods("unique")
>                splus            splus          menu                 splus 
>  "unique.data.frame" "unique.default" "unique.name" "unique.rowcol.names"
> 
> 
> In R-1.9.1:
> 
> > methods("unique")
> [1] unique.array      unique.data.frame unique.default    unique.matrix    
> 
> 
> Unless there's some sort of coordination (or even just separate effort) on
> either/both R Core and Insightful developers to make sure there's agreement
> on what methods to provide in the base code, such problem can only get
> worse, not better, I guess.

There are plans to that effect, but R moves much faster than a commercial 
product such as S-PLUS.

It seems to me a bad idea that unique (or foo) does different things for 
matrices and data frames, for as we see frequently, many users do not 
distinguish between them.

-- 
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