Re: [R] Error with lapply [addirional clarification needed]
Try str(ss) to see what it really looks like. You probably want: fn <- function(i) c(i, i^2) On Sat, Nov 22, 2008 at 4:54 AM, megh <[EMAIL PROTECTED]> wrote: > > I need one more clarification here : > > Here I did : > > fn <- function(i) return(list(i, i^2)) > ss = sapply(1:4, fn) > > Here the object "ss" should be a matrix object : > is.matrix(ss) > > However I feel it lacks some the matrix object properties. For example the > syntax "min(ss[1,])" generates an error : > "Error in min(ss[1, ]) : invalid 'type' (list) of argument". > > What should be the way out? Am I missing something ? > > Regards, > > > baptiste auguie-2 wrote: >> >> Hi, >> >> you are feeding lapply "i" as an optional argument, which is passed to >> fn() and causes an error. Just use lapply(1:4, fn), or better yet, >> sapply, >> >> > fn <- function(i) return(i^2) >> > sapply(1:4, fn) >> [1] 1 4 9 16 >> >> Hope this helps, >> >> baptiste >> >> >> On 20 Nov 2008, at 16:31, megh wrote: >> >>> >>> I have written following codes, with intention to get a list with >>> values >>> 1,2,9,16 : >>> >>> fn <- function(i) return(i^2) >>> lapply(1:4, fn, i) >>> >>> However I got following error : >>> Error in FUN(1:4[[1L]], ...) : unused argument(s) (1) >>> >>> Can anyone please tell me what will be the correct code here? >>> >>> Regards, >>> >>> >>> -- >>> View this message in context: >>> http://www.nabble.com/Error-with-lapply-tp20605066p20605066.html >>> Sent from the R help mailing list archive at Nabble.com. >>> >>> __ >>> 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. >> >> _ >> >> Baptiste Auguié >> >> School of Physics >> University of Exeter >> Stocker Road, >> Exeter, Devon, >> EX4 4QL, UK >> >> Phone: +44 1392 264187 >> >> http://newton.ex.ac.uk/research/emag >> >> __ >> 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. >> >> > > -- > View this message in context: > http://www.nabble.com/Error-with-lapply-tp20605066p20634821.html > Sent from the R help mailing list archive at Nabble.com. > > __ > 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. > __ 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.
Re: [R] Error with lapply [addirional clarification needed]
megh wrote: I need one more clarification here : Here I did : fn <- function(i) return(list(i, i^2)) ss = sapply(1:4, fn) Here the object "ss" should be a matrix object : is.matrix(ss) However I feel it lacks some the matrix object properties. For example the syntax "min(ss[1,])" generates an error : "Error in min(ss[1, ]) : invalid 'type' (list) of argument". What should be the way out? Am I missing something ? ss is a dim'ed list object, because fn returns a list. This appears to be a feature, although rarely used. One point is that you can do > fn <- function(i) return(list(as.character(i), i^2)) > ss <- sapply(1:4, fn) > ss [,1] [,2] [,3] [,4] [1,] "1" "2" "3" "4" [2,] 14916 > ss[,1] [[1]] [1] "1" [[2]] [1] 1 I.e., the rows can be of different mode. The easiest way out is just not to do that, i.e. return a vectore c(i, i^2) instead. -- O__ Peter Dalgaard Øster Farimagsgade 5, Entr.B c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907 __ 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.
Re: [R] Error with lapply [addirional clarification needed]
I need one more clarification here : Here I did : fn <- function(i) return(list(i, i^2)) ss = sapply(1:4, fn) Here the object "ss" should be a matrix object : is.matrix(ss) However I feel it lacks some the matrix object properties. For example the syntax "min(ss[1,])" generates an error : "Error in min(ss[1, ]) : invalid 'type' (list) of argument". What should be the way out? Am I missing something ? Regards, baptiste auguie-2 wrote: > > Hi, > > you are feeding lapply "i" as an optional argument, which is passed to > fn() and causes an error. Just use lapply(1:4, fn), or better yet, > sapply, > > > fn <- function(i) return(i^2) > > sapply(1:4, fn) > [1] 1 4 9 16 > > Hope this helps, > > baptiste > > > On 20 Nov 2008, at 16:31, megh wrote: > >> >> I have written following codes, with intention to get a list with >> values >> 1,2,9,16 : >> >> fn <- function(i) return(i^2) >> lapply(1:4, fn, i) >> >> However I got following error : >> Error in FUN(1:4[[1L]], ...) : unused argument(s) (1) >> >> Can anyone please tell me what will be the correct code here? >> >> Regards, >> >> >> -- >> View this message in context: >> http://www.nabble.com/Error-with-lapply-tp20605066p20605066.html >> Sent from the R help mailing list archive at Nabble.com. >> >> __ >> 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. > > _ > > Baptiste Auguié > > School of Physics > University of Exeter > Stocker Road, > Exeter, Devon, > EX4 4QL, UK > > Phone: +44 1392 264187 > > http://newton.ex.ac.uk/research/emag > > __ > 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. > > -- View this message in context: http://www.nabble.com/Error-with-lapply-tp20605066p20634821.html Sent from the R help mailing list archive at Nabble.com. __ 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.
