From ripley@stats.ox.ac.uk  Tue Dec  3 14:51:02 2002
From: ripley@stats.ox.ac.uk (ripley@stats.ox.ac.uk)
Date: Tue Dec  3 14:51:02 2002
Subject: [Rd] small inconsistency in sort
In-Reply-To: <Pine.LNX.4.21.0212031421030.5202-100000@artemis>
Message-ID: <Pine.LNX.4.31.0212031344010.31998-100000@gannet.stats>

On Tue, 3 Dec 2002, Torsten Hothorn wrote:

> if an atomic with colnames / rownames attribute is sorted, its names are
> not sorted in the appropriate way:
>
> R> a <- matrix(1:5, ncol=5)
> R> colnames(a) <- paste("V", 1:5, sep="")
> R> a
>      V1 V2 V3 V4 V5
> [1,]  1  2  3  4  5
> R> sort(a, dec=TRUE)
>      V1 V2 V3 V4 V5
> [1,]  5  4  3  2  1
> R>
>
> ?sort states that x is `a numeric or complex vector' but sort only checks
> if `is.atomic(x)' causing the small problem.

Where is the inconsistency?  Nothing I can see says that arbitrary
attributes of a vector will be sorted, and a (numeric or complex) array
*is* a (numeric or complex) vector with some extra attributes.

How can one possibly sort a matrix *and* its dimnames except for
one-dimensional arrays?  Sorting a matrix makes no sense except when it is
regarded as a vector, and if that makes sense it probably also makes sense
to leave the dimnames unchanged.

-- 
Brian D. Ripley,                  ripley@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 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595



[Rd] small inconsistency in sort
ripley@stats.ox.ac.uk