Storing Multiple Matrices from a For Loop

How do I index and store multiple matrices as a run through a for loop? For instance, I generate a 10x10 matrix the first time through and I want to store this result for access later before proceeding to the next matrix generation.

Answer 1

[Cedric]

You can use a cell array, e.g

 n = 10 ;
 M = cell(n, 1) ;
 for k = 1 : n
    M{k} = 20*k + rand(10) ;
 end

you can see that each

 M{1}, M{2}, etc

is a the 10x10 matrix defined at a specific iteration of the loop.

Note the difference between regular block indexing with () and accessing cells content with {}:

 M(1)

is cell #1 of the cell array M, whereas

 M{1}

is the content of cell #1 (in the present case, it is a 10x10 matrix).

[Anthony Uwaechia]

this is actually an intelligent way of saving matrix from loop iterations. thanks a lot. it really solved my problem

[Swathi Chandrasekar]

Amazing.Thanks

[Alvina Khairun Nisa]

Can I save m{k} to .mat file?

[Stephen23]

@Alvina Khairun Nisa: allocate it to a temporary variable and save that, e.g.:

for k = 1:N
    data = m{k};
    fnm = sprintf('file_%d.mat',k);
    save(fnm,'data');
end

[Irfan Azhar]

very helpful. thanks indeed.

[Mohammad Kifayath Chowdhury]

Thanks a lot.

[Redouane Bouchou]

thank you , that was very helpfeul

[Himanshu Banait]

Thanks a lot.

[Malik haseeb Haider]

many thanks

[mary john]

thanks a lot

[Marcio Pereira]

Very good! Grateful!

[Lukas Leitenbacher]

You´re the real MVP, man! Thx a lot for this approach!

[Ali Berenjian]

thanks a lot!

[Bryan Guilcapi]

Hi, i have a question, is possible to plot all this cell in one plot calling the data that are inside of the cell?

[Walid]

thank you

Answer 2

[Saeed Bello]

You can use a three-dimensional matrix e.g.

for i = 1:8 % no. of iteration
  S(:, :, i) = myfunx(i,10); % 10 x 10 output
end

Then you can access each iteration by calling S(:, : , 1) or S(:, : , 2) or S(:, : , 3) and so on. Source:https://stackoverflow.com/questions/30036908/output-of-for-loop-as-a-matrix-matlab

[Irfan Azhar]

many thanks indeed.

[ELIAS PERATICOS]

Saeed Bello, thanks a lot this was very useful.

[rees adah]

I also have a similar problem but this solution didn't work for me.i intend to store the matrices coming from a nested for loop into a multidimensional array and reference it later...how do I do that please?

Answer 3

[D.K. Rao]

Thank you very much Cedric Wannaz