Re: [R] Evaluation of defaults in functions

From: Gabor Grothendieck <ggrothendieck_at_gmail.com>
Date: Fri 29 Sep 2006 - 14:37:33 GMT

On 9/29/06, hadley wickham <h.wickham@gmail.com> wrote:
> > > But doesn't R has a rather limited force of lazy evaluation? - you
> > > have no control over it, apart from that arguments are evaluated
> > > lazily. This rather limited compared to other languages (no lazy
> > > lists etc)
> >
> > You do have more control than that. You can't put a promise in a list,
> > but you can put one in an environment, e.g.
> >
> > > x <- new.env()
> > > y <- 1
> > > delayedAssign("z", y, assign=x)
> > > y <- 2
> > > x$z
> > [1] 2
>
> That's interesting. Is it possible to treat an environment like a
> list in most situations?
>
> I had experimented with lazy lists/streams in R a while go (as they
> seem like a very natural way of dealing with datasets that are too
> large to fit in memory) but got stuck. This might let me get a little
> further.
>

Check out the g.data package.



R-help@stat.math.ethz.ch 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. Received on Sat Sep 30 00:55:30 2006

Archive maintained by Robert King, hosted by the discipline of statistics at the University of Newcastle, Australia.
Archive generated by hypermail 2.1.8, at Fri 29 Sep 2006 - 15:30:06 GMT.

Mailing list information is available at https://stat.ethz.ch/mailman/listinfo/r-help. Please read the posting guide before posting to the list.