Did you ever receive a reply to this? Note that for your example: > tapply(l,index,sum) Error in FUN(X[[i]], ...) : invalid 'type' (list) of argument
A list is definitely not atomic (is.recursive(l) ). So it looks like a "quirk" that FUN = unlist doesn't raise an error. Cheers, Bert Bert Gunter "The trouble with having an open mind is that people keep coming along and sticking things into it." -- Opus (aka Berkeley Breathed in his "Bloom County" comic strip ) On Sat, Feb 4, 2017 at 4:17 AM, Tal Galili <tal.gal...@gmail.com> wrote: > In the help page of ?tapply it says that the first argument (X) is "an > atomic object, typically a vector." > > However, tapply seems to be able to handle list objects. For example: > > ################### > > l <- as.list(1:10) > is.atomic(l) # FALSE > index <- c(rep(1,5),rep(2,5)) > tapply(l,index,unlist) > >> tapply(l,index,unlist) > $`1` > [1] 1 2 3 4 5 > > $`2` > [1] 6 7 8 9 10 > > > ################### > > Hence, does it mean a list an atomic object? (which I thought it wasn't) or > is the help for tapply needs updating? > (or some third option I'm missing?) > > Thanks. > > > > > > ----------------Contact > Details:------------------------------------------------------- > Contact me: tal.gal...@gmail.com | > Read me: www.talgalili.com (Hebrew) | www.biostatistics.co.il (Hebrew) | > www.r-statistics.com (English) > ---------------------------------------------------------------------------------------------- > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.
