Elementary question, for loop implementation

I need to implement "for" loop:

I have 5 matrices, m1,m2,m3,m4,m5 of size 2x3.

in first for loop:

A=m1 (size 2x3)

B=[m2,m3,m4,m5 as they joined together, size 2x12]

in second loop

A=m2

B=[m1,m3,m4,m5]

and so on

(Basically, each time A is one of matrices, B is remaining matrices)

[madhan ravi]

please don't post the same question again and again (https://www.mathworks.com/matlabcentral/answers/430460-easy-for-loop-implementation-cell-array#comment_638812)

Answer 1

[Guillaume]

As we've just said in your previous question, do not create numbered arrays. It's always the wrong approach, as you can see now, it's very hard to work with.

Instead of 5 matrices of size 2x3 you should either have a single 2x3x5 matrix or a 1x5 cell array of 2x3 matrices. Whichever you prefer. Either way, your loop is then very easy to write:

%with a single 2x3x5 matrix called m
%note that the code works with any size matrix. It makes no assumption about their size
for i - 1:size(m, 3)
    A = m(: :, i);
    B = m(:, :, [1:i-1, i+1:end]);
    B = reshape(permute(B, [2 3 1]), [], size(B, 1)).'
   %do something with A and B
end

%with a single 1x5 cell array of matrices
%note that the code works for any size cell array and matrices, as long as all the matrices are the same size
for i = 1:numel(C)
    A = C{i};
    B = [C{[1:i-1, i+1:end]}];
end

If for some reason, you cannot change the way you create these numbered variables, you can remediate the problem after the fact with:

m = cat(3, m1, m2, m3, m4, m5);  %for a 3d matrix
m = {m1, m2, m3, m4, m5};  %for a cell array