Hadley,

Your request is reminding me of the analysis of aray functions in Philip S
Abrams dissertation
http://www.slac.stanford.edu/cgi-wrap/getdoc/slac-r-114.pdf
AN APL MACHINE

The section that starts on page 17 with this paragraph is the one that
immediately applies

C. The Standard Form for Select Expressions

In this section the selection operators considered are take, drop, reversal,
transpose, and subscripting by scalars or _J-vectors. Because of the
similarity
among the selection operators, we might expect that an expression
consisting only
of selection operators applied to a single array could be expressed
equivalently in
terms of some simpler set of operators. This expectation is fulfilled in the
standard form for select expressions, to be discussed below.

I look forward to seeing where you take this in R.

Rich

On Mon, Jan 2, 2012 at 8:38 AM, Hadley Wickham <hadley@rice.edu> wrote:

> > But if not,  it seems to me that it should be added as an array method
> > to ?rev with an argument specifying which indices to rev() over.
>
> Yes, agreed.  Sometimes arrays seem like something bolted onto R that
> is missing a lot of functionality.
>
> Hadley
>
> --
> Assistant Professor / Dobelman Family Junior Chair
> Department of Statistics / Rice University
> http://had.co.nz/
>
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