Thanks Henrique. I would have not thought of the syntax you suggest, though it embodies the sort of multilevel (not quite recursive) application of lapply I was thinking of. However, it returns ³test² with V2 missing, everything else intact. Strange; I can't really state in words what I think it should do, much less what it does do!
I think an easier approach for me will be to re-write the function that generates "test" so it is simpler to extract what I need. I will think on it. Thanks, Bryan > temp <- lapply(test, lapply, '[', 'V1') > str(temp) List of 2 $ G:List of 4 ..$ cls:'data.frame': 101 obs. of 1 variable: .. ..$ V1: num [1:101] -0.0019 -0.0019 -0.00189 -0.00188 -0.00186 ... ..$ rob:'data.frame': 101 obs. of 1 variable: .. ..$ V1: num [1:101] -0.00142 -0.00141 -0.0014 -0.00139 -0.00137 ... ..$ c : num NA ..$ r : num NA $ T:List of 4 ..$ cls:'data.frame': 101 obs. of 1 variable: .. ..$ V1: num [1:101] -0.00222 -0.00222 -0.00221 -0.00219 -0.00216 ... ..$ rob:'data.frame': 101 obs. of 1 variable: .. ..$ V1: num [1:101] -0.000981 -0.000979 -0.000972 -0.000961 -0.000946 .. ..$ c : num NA ..$ r : num NA On 8/11/09 7:28 PM, "Henrique Dallazuanna" <www...@gmail.com> wrote: > If I understand correctly your question, you can try something about like > this: > > # Access all elements named 'V1' in your list > lapply(test, lapply, '[', 'V1') > > > On Tue, Aug 11, 2009 at 3:49 PM, Bryan Hanson <han...@depauw.edu> wrote: >> Hello Again R Folks: >> >> I¹m trying to clean up some code. Suppose I have an object like this: >> >>> str(test) >> List of 2 >> $ G:List of 2 >> ..$ cls:'data.frame': 101 obs. of 2 variables: >> .. ..$ V1: num [1:101] -0.0019 -0.0019 -0.00189 -0.00188 -0.00186 ... >> .. ..$ V2: num [1:101] 0.000206 0.000247 0.000288 0.000329 0.000371 ... >> ..$ rob:'data.frame': 101 obs. of 2 variables: >> .. ..$ V1: num [1:101] -0.00142 -0.00141 -0.0014 -0.00139 -0.00137 ... >> .. ..$ V2: num [1:101] 0.000424 0.000456 0.000487 0.000517 0.000546 ... >> $ T:List of 2 >> ..$ cls:'data.frame': 101 obs. of 2 variables: >> .. ..$ V1: num [1:101] -0.00222 -0.00222 -0.00221 -0.00219 -0.00216 ... >> .. ..$ V2: num [1:101] -0.00077 -0.000742 -0.000712 -0.000681 -0.000648 >> .. >> ..$ rob:'data.frame': 101 obs. of 2 variables: >> .. ..$ V1: num [1:101] -0.000981 -0.000979 -0.000972 -0.000961 -0.000946 >> .. >> .. ..$ V2: num [1:101] -0.000332 -0.000303 -0.000274 -0.000245 -0.000216 >> .. >> >> I need to perform some operations on each value of V1 in turn, then each >> value of V2 in turn (so for instance I want test$G$cls$V1). The structure >> of this object is nearly constant except the first elements of the list (G, >> T in the example) may vary in number and name, so I need something that >> accommodates this. >> >> I can do this with loops, but it seems like a job for lapply or rapply, but >> these don't quite work. I've played with quite a few variations, searched >> the help archives and found a number of useful ideas, but not quite what I >> need. The only thing that nearly works is do.call(cbind, object) enough >> times to bring V1 and V2 "to the surface" but then I've lost my carefully >> constructed naming. >> >> Any suggestions appreciated. It seems like there might be a simple >> approach, but I may be too tired right now to see it! >> >> Thanks, Bryan >> ************* >> Bryan Hanson >> Professor of Chemistry & Biochemistry >> DePauw University, Greencastle IN USA >> >> ______________________________________________ >> 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.
