MATLAB: What’s the solution

For example: If I have matrix A and Matrix B:
A =
     7     4     1
     4     5     6
     3     6     9
>> B = zeros(4,4)
B =
     0     0     0     0
     0     0     0     0
     0     0     0     0
     0     0     0     0
I want I want element (3,2) from matrix B with size (4,4) to try the values of the first column from matrix A with size (3,3) one by one and at each time produce the new matrix. So, the output will be:
B =
     0     0     0     0
     0     0     7     0
     0     0     0     0
     0     0     0     0
B =
     0     0     0     0
     0     0     4     0
     0     0     0     0
     0     0     0     0
B =
     0     0     0     0
     0     0     3     0
     0     0     0     0
     0     0     0     0
How can I do this ?

Best Answer

Here is one easy way, by generating one 3D array B and allocating all values of A in one go:
>> A = [7,4,1;4,5,6;3,6,9];
>> B = zeros(4,4,numel(A));
>> B(2,3,:) = A(:);
and testing each page of B, shows that it has all of the correct matrices:
>> B(:,:,1)
ans =
   0   0   0   0
   0   0   7   0
   0   0   0   0
   0   0   0   0
>> B(:,:,2)
ans =
   0   0   0   0
   0   0   4   0
   0   0   0   0
   0   0   0   0
>> B(:,:,3)
ans =
   0   0   0   0
   0   0   3   0
   0   0   0   0
   0   0   0   0
>> B(:,:,4)
ans =
   0   0   0   0
   0   0   4   0
   0   0   0   0
   0   0   0   0
etc
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