How to correctly store and access data in a 4D array?

Suppose I store some 2-by-2 matrices in a 4D array as following

data = zeros(10,5,2,2);

for i = 1:10
    for j = 1:5
        a = [i+j, 0;
            i-j, 0];
        data(i,j,:,:) = a;
    end
end

later, I want to acess these 2-by-2 matrices. How can I correctly access them? Is the following way a correct way?

i = 2;
j = 5;

matrix = reshape( data(i,j,:,:), 2, 2)

I have tested this method for several i and j. it seems to work, but I am not sure if this always gives correct result.

[Dyuman Joshi]

"Is the following way a correct way?"

Yes, it is correct.

[Stephen23]

"Is the following way a correct way?"

It seems to be. If you permute the dimensions of that matrix then you would not need to RESHAPE all the time.

Note: explicit RESHAPE is better than uncontrolled SQUEEZE.

Answer 1

[Hassaan]

It can be and other way could be:

% Initialize a 4D array to store 2-by-2 matrices
data = zeros(10,5,2,2);

% Fill the array with 2-by-2 matrices
for i = 1:10
    for j = 1:5
        a = [i+j, 0;
             i-j, 0];
        data(i,j,:,:) = a;
    end
end

% Access a specific 2-by-2 matrix without reshape
i = 2;
j = 5;
matrix = squeeze(data(i,j,:,:));

% Display the accessed matrix
disp(matrix);

     7     0
    -3     0

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