Thanks, Gabor and Prof. Ripley. Sorry for the oversight.
I grepped the lapply help for recursive prior to sending my question. why does it appear as "*r*ecursive" in the help file? or is that just a formating problem on my machine? -Whit On Thu, Dec 11, 2008 at 3:13 PM, Prof Brian Ripley <rip...@stats.ox.ac.uk> wrote: > On Thu, 11 Dec 2008, Whit Armstrong wrote: > >> for a simple example: >> >> x <- list() >> x[["a"]] <- list(a=c(1,2,3),b=c(3,4,5)) >> x[["b"]] <- list(a=c(6,7,8),b=c(9,10,11)) >> >> lapply(x,sum) >> >> >> this fails w/ >> Error in FUN(X[[1L]], ...) : invalid 'type' (list) of argument >> >> Just wondering if I have overlooked something obvious. > > rapply? Which is linked from ?lapply (I just checked). Perhaps > >> rapply(x, sum) > > a.a a.b b.a b.b > 6 12 21 30 > > or > >> rapply(x, sum, how="list") > > $a > $a$a > [1] 6 > ..... > >> >> one can also do: >> >> lapply(x,lapply,sum) >> >> but that assumes that you already know how many levels you have, and >> that all the levels are consistent. >> >> -Whit >> >> ______________________________________________ >> 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. >> > > -- > Brian D. Ripley, rip...@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 272866 (PA) > Oxford OX1 3TG, UK Fax: +44 1865 272595 > ______________________________________________ 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.