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 <hanson@depauw.edu> wrote:

> Hello Again R Folks:
>
> Išm 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
>
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> and provide commented, minimal, self-contained, reproducible code.
>



-- 
Henrique Dallazuanna
Curitiba-Paraná-Brasil
25° 25' 40" S 49° 16' 22" O

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