On Wed, 10 Mar 2004, Robin Hankin wrote:
>
> Hi everyone.
>
> I'm playing with aperm():
>
> a <- 1:24
> dim(a) <- c(2,3,2,2)
> permutation <- c(1,2,4,3)
> b <- aperm(a,permutation)
>
>
> So if my understanding is right,
>
> a[1,3,2,1] == b[c(1,3,2,1)[permutation] ]
>
> but this isn't what I want because the RHS evaluates to a vector, and
> I am trying to identify a single element of b.
>
> How do I modify the RHS to give what I want?
ind <- as.list(c(1,3,2,1)[permutation])
do.call("[", c(list(b), ind))
--
Brian D. Ripley, [EMAIL PROTECTED]
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
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