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 <had...@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/ > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html<http://www.r-project.org/posting-guide.html> > and provide commented, minimal, self-contained, reproducible code. > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
