MATLAB: How to use an array of coordinate pairs to index into 2D array

2darraycoordinateindexinglinearMATLABsub2ind

I have a 2D array, "A":
>> A = reshape([1:25],5,5)
A =
       1     6    11    16    21
       2     7    12    17    22
       3     8    13    18    23
       4     9    14    19    24
       5    10    15    20    25
and I have coordinate pairs (x,y) stored in array "B":
>> B = [ 1 1; 2 2; 3 3]
B =
       1     1
       2     2
       3     3
How can I use "B" to access "A" such that I get something like:
>> A(B)
ans =
       1
       3
       7

Best Answer

You can use the "sub2ind" function to convert the coordinates into linear index of the array and then access the elements:
>> I = sub2ind(size(A),B(:,1),B(:,2));
>> A(I)
ans =
       1
       3
       7
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