MATLAB: Hello, I didn’t get the following code:

component-wise indexing with arraysMATLAB

 M = reshape(linspace(11,18,8),[2,2,2])
 M([1,2],[2,1],[2,1])
 A1 = [2,2;2,1];    v = [2,1];
 M(A1,v,1)
*****************************
 ans =
    14    12
    14    12
    14    12
    13    11
i didnt get this ans, more precisely, im confused that what A1=[2,2;2,1] in M(A1,v,1) do???
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Best Answer

This is all simple indexing which I thought was well explained in the doc
   M([1,2],[2,1],[2,1])
returns row 1 and 2, column 2 and 1 (in that order) and page 2 and 1 (in that order) of M.
A1 = [2,2;2,1];    
v = [2,1];  
M(A1,v,1)
Note that the shape of A1 is irrelevant in the above. A1 = [2 2 2 1] would produce the same result. It returns row 2, then row 2 again, then row 2 again, then row 1 and column 2 and 1 (in that order) and page 1.
    v(1)                = index column 2  
     |     v(2)         = index column 1
     |     |
     V     V
    14    12  <-- A1(1) = index row 2
    14    12  <-- A1(2) = index row 2
    14    12  <-- A1(3) = index row 2
    13    11  <-- A1(4) = index row 1
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