[R] Recursive Indexing Failed

[Duncan Murdoch]

On 09/05/2011 9:18 AM, Patrick Breheny wrote:
> On 05/09/2011 08:58 AM, Alaios wrote:
> >  Dear all,
> >  I would like to ask your help concerning an error message I get.
> >
> >  I have the following struct
> >
> >  str(CRagentInTime[[1]])
> >  List of 2
> >    $ timelag: int 0
> >    $ CRagent:List of 50
> >     ..$ :List of 3
> >     .. ..$ CRmap: num [1:256, 1:256] NA NA NA NA NA NA NA NA NA NA ...
> >     .. ..$ xy   : num [1:2] 10 177
> >     .. ..$ sr   : num [1:49] -94.9 -92.8 -79.5 -97.6 -78.4 ...
> >
> >  and I wanted to select all the sr fields for every of each one of the 50 CRagent Lists I have.
> >
> >  So I tried something like
> >
> >  str(CRagentInTime[[1]][[2]][[1:10]]$sr) and I get a message that
> >  Error in CRagentInTime[[1]][[2]][[1:10]] :
> >     recursive indexing failed at level 3
>
> Selecting multiple elements of a list using an expression like [[1:10]]
> does not work.  For example:
>
> x<- list("a","b")
> x[[1:2]]
>
> produces
>
> Error in x[[1:2]] : subscript out of bounds
>
> In general, the expression x[[1:2]] is not meaningful, as the elements
> of the list may be of different type, with no way to concatenate them.

That's the wrong explanation:  the expression x[[1:2]] is meaningful, 
but it means the same thing as x[[1]][[2]], not
c(x[[1]], x[[2]]).

Duncan Murdoch
> >
> >  strange to me is that this one works
> >
> >  str(CRagentInTime[[1]][[2]][[1]]$sr)
> >    num [1:49] -106 -92.9 -101.3 -81.9 -96.7 ...
> >
> >
> >  I would like to thank you in advance for your help
> >  Best Regards
> >  Alex
> >
> _______________________
> Patrick Breheny
> Assistant Professor
> Department of Biostatistics
> Department of Statistics
> University of Kentucky
>
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