[R] Arrays of variable dimensionality

[William Dunlap]

I don't know for sure what result you want, but it may be that
using a length(dim(array))-column matrix as your subscript will
do what you want.  E.g.,
  > a <- array(101:124, dim=4:2)
  > subscriptMatrix <- cbind(c(1,3), c(2,2), c(2,1))
  > subscriptMatrix
       [,1] [,2] [,3]
  [1,]    1    2    2
  [2,]    3    2    1
  > a[subscriptMatrix]
  [1] 117 107
  > a[1, 2, 2]
  [1] 117
  > a[3, 2, 1]
  [1] 107


Bill Dunlap
TIBCO Software
wdunlap tibco.com

On Sat, May 30, 2015 at 3:29 AM, WRAY NICHOLAS <nicholas.wray at ntlworld.com>
wrote:

> Hello folks
>
> Supposing I have a multidimensional array in an R prog, say a 4D array.
>
> I want the coordinate quantities to be read off from a vector.  The values
> in the vector (vec) are generated by a function.
>
> This is easy if the number of dimensions is fixed for both the array and
> the number of elements in the  vector (say 4):
>
> X<-array[vec[1],vec[2],vec[3],vec[4]]
>
> But if the number of dimensions of the array is not fixed and can change
> during the course of the prog I am stuck as to how to do this, as I don’t
> know a way of feeding a vector or list of unspecified beforehand length
> into the coordinates for an array
>
> I can’t find anything useful about this on the net
>
> Does anyone have any ideas?
> Thanks, Nick
>
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