R: How to extract sets of multidimensional array values according to another matrix

Question

Suppose I have a 4 dimensional n x n x n x n array A. A is a distance matrix, such that A[i,j,l,k] is the distance from location i,j to location pair l,k. Suppose I have an nxn

Answer 1

I guess you have changed the request from the one stated in the first paragraph. See if this answers the second version.

 A [ cbind( which(T == 0, arr.ind=TRUE), which(T == 1, arr.ind=TRUE) )]
#[1] 1 1

(At first I thought you might need abind but cbind works fine.)