MATLAB: Combine three matrices (every other column)

combinationevery othermatrix

I have three matrices A, B and C which are for example
A=[A11 A12 A13; A21 A22 A23; A31 A32 A33] , B=[B11 B12 B13; B21 B22 B23; B31 B32 B33] and C=[C11 C12 C13; C21 C22 C23; C31 C32 C33]
I would like to combine these matrices so that every other column is from A, B and C. Hence the resulting matrixshould be:
[A11 B11 C11 A12 B12 C12 A13 B13 C13; A21 B21 C21 A22 B22 C22 A23 B23 C23; A31 B31 C31 A32 B32 C32 A33 B33 C33]
My matrices are not only 3×3 matrices but 26 x 100 matrices so the resulting matrix should be 78×100. If I use
D=reshape([A;B;C], size(A,1), []);
I get the right order but my matrix is 26×100. If I use
D=reshape([A;B;C], [], size(A,2));
I get the right size but the order of the elements is wrong.
Since I don't have a lot of experience with Matlab, could you please help me figure out how to solve my problem?

Best Answer

Or, as a one-liner, using left-hand indexing:
% some test data
A = cumsum(ones(5,4),2), B = 10 * A, C = 10 * B
% left-hand indexing trick (NewMatrix should not exist)
NewMatrix(:, (1:3) + (1:3:3*size(A,2)).' - 1) = [A B C]
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