Thanks to everybody who replied - I got three distinct, very useful suggestions.
Bjarke Christensen Romain Francois <romain.francois@ dbmail.com> Til Bjarke Christensen 19-11-2009 14:33 <bjarke.christen...@sydbank.dk> cc r-help@r-project.org Emne Re: [R] Accessing list names in lapply Maybe this : http://tolstoy.newcastle.edu.au/R/e4/help/08/04/8720.html Romain On 11/19/2009 01:27 PM, Bjarke Christensen wrote: > Hi, > > When using lapply (or sapply) to loop over a list, can I somehow access the > index of the list from inside the function? > > A trivial example: > > df1<- split( > x=rnorm(n=100, sd=seq(from=1, to=10, each=10)), > f=letters[seq(from=1, to=10, each=10)] > ) > str(df1) > #List of 10 > # $ a: num [1:10] -0.801 0.418 1.451 -0.554 -0.578 ... > # $ b: num [1:10] -2.464 0.279 4.099 -2.483 1.921 ... > # $ c: num [1:10] -1.14 -1.773 2.512 -2.072 -0.904 ... > # $ d: num [1:10] 2.109 1.243 0.627 -2.343 -6.071 ... > #... > par(mfcol=c(5,2)) > lapply(df1, plot) > > This plots each element of the list, but the label on the vertical axis is > X[[0L]] (as expected from the documentation in ?lapply). I'd like the > heading for each plot to be the name of that item in the list. This can be > achieved by using a for-loop: > > for (i in names(df1)) plot(df1[[i]], ylab=i) > > but can it somehow be achieved bu using lapply? I would be hoping for > something like > > lapply(df1, function(x) plot(x, ylab=parent.index())) > > or some way to parse the index number out of the call, using match.call() > or something like that. > > Thanks in advance for any comments, > Bjarke Christensen -- Romain Francois Professional R Enthusiast +33(0) 6 28 91 30 30 http://romainfrancois.blog.free.fr |- http://tr.im/EAD5 : LondonR slides |- http://tr.im/BcPw : celebrating R commit #50000 `- http://tr.im/ztCu : RGG #158:161: examples of package IDPmisc ______________________________________________ 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.