How to convert a cell array to a compatible matrix?

I have a cell array which is filled with matrices of varying size, could you help me to convert it to matrix with filling zeros at in between columns,

in this case the matrix size is ought ot be 41x 41 of double type.

[KSSV]

Fill the empty cells with appropriate zero matrices and use Cell2mat.

Answer 1

[Jan]

CC = {rand(9,9), rand(5,4), rand(5,4), rand(6,4), rand(6,4), rand(8,4), rand(8,4), rand(9,4), rand(9, 4); ...
    rand(4,5), rand(4,4), [], [], [], [], [], [], []; ...
    [], [], rand(4,4), [], [], [], [], [], []; ...
    rand(4,6), [], [], rand(4,4), [], [], [], [], []; ...
    [], [], [], [], rand(4,4), [], [], [], []; ...
    rand(4,6), [], [], [], [], rand(4,4), [], [], []; ...
    [], [], [], [], [], [], rand(4,4), [], []; ...
    rand(4,6), [], [], [], [], [], [], rand(4,4), []; ...
    [], [], [], [], [], [], [], [], rand(4,4)};

C     =  CC;
S1    = cellfun('size', C, 1);
maxS1 = max(S1, [], 2);
S2    = cellfun('size', C, 2);
maxS2 = max(S2, [], 1);

for i2 = 1:size(C, 2)
   for i1 = 1:size(C, 1)
       X = C{i1, i2};
       if size(X, 1) < maxS1(i1) || size(X, 2) < maxS2(i2)
          X(maxS1(i1), maxS2(i2)) = 0;
          C{i1, i2} = X;
       end
   end
end
Result = cell2mat(C);

Cheaper:

C     = CC;
S1    = cellfun('size', C, 1);
maxS1 = max(S1, [], 2);
S2    = cellfun('size', C, 2);
maxS2 = max(S2, [], 1);
Result2 = zeros(sum(maxS1), sum(maxS2));

c1 = 1;
for i1 = 1:size(C, 1)
    c2 = 1;
   for i2 = 1:size(C, 2)
       X = C{i1, i2};
       Result2(c1:c1 + size(X,1) - 1, c2:c2 + size(X,2) - 1) = X;
       c2 = c2 + maxS2(i2);
   end
   c1 = c1 + maxS1(i1);
end

isequal(Result, Result2)

ans = logical
   1

It took some tome to create some test data as input. Please care for providing some code, which creates your input data, to make answering as easy as possible.

[Nandha Kumar]

I was pretty occupied with sorting it out myself sir, and this is my first question and I never thought it would be answered sir, that has been the experience with other forum questions of mine so far, so it slipped my mind.

Aplogies for the inconvenience caused.

Thank you so much sir, for the time, effort and the knowledge sharing sir,

Thanks

P.S: I m decently good with use of arrays and linear algebra, but when something of this sort comes up, I m stumped,. is there any book or course you would suggest sir, for learning to use cells, and other hidden gems of MATLAB, which might be quite useful? If so kindly suggest, thanks

[Image Analyst]

@Nandha Kumar, to learn MATLAB, see these links:

Best way(s) to master MATLAB? - MATLAB Answers - MATLAB Central

https://matlab.fandom.com/wiki/FAQ#What_is_a_cell_array.3F

MATLAB Academy - Free 2 hour training

[Nandha Kumar]

@Image Analyst Thank you sir, I ll learn from it.