How to create an array of matrices?

If I have 3 matrices:

A = [1 2 ; 3 4]
B = [5 6 ; 7 8]
C = [9 10 ; 11 12]

And I want to create a greater matrix with these inside like D = [A ; B ; C], that would result in something like:

D = [1 2 ; 5 6 ; 9 10

3 4 ; 7 8 ; 11 12 ]

I have tried writing something as simple as

D = [A , B , C]

But this solely puts all these matrices side by side into a single matrix, whilst I intend to keep them all separately in an array, to create a "row" of matrices...

Answer 1

[the cyclist]

You could use a cell array:

A = [1 2 ; 3 4];
B = [5 6 ; 7 8];
C = [9 10 ; 11 12];

D = {A, B, C}

D = 1×3 cell array
    {2×2 double}    {2×2 double}    {2×2 double}

I think the best answer will depend on what you are planning on doing with the result afterward.

[Goncalo Costa]

I am trying to go through each matrix in a for loop. But when I tried writing it that way, I thought that the answer you showed below meant it hadn't worked, and that therefore I couldn't use this for a for loop.

Thank you so much for your help.

Answer 2

[the cyclist]

Given your comment on my other answer, another possible solution is to stack the matrices as slices in a 3rd dimension:

A = [1 2 ; 3 4];
B = [5 6 ; 7 8];
C = [9 10 ; 11 12];

D = cat(3,A,B,C);

for ii = 1:3
    D(:,:,ii)
end

ans = 2×2

1 2 3 4

ans = 2×2

5 6 7 8

ans = 2×2

9 10 11 12

Answer 3

[Thomas]

function aM = arrayofmatrices(A,B,C)

aM(:,:,1) = A;

aM(:,:,2) = B;

aM(:,:,3) = C;

end

This only works when A, B and C have the same sidelenths. If not you need a cell array.