How to concentrate matrix 100 times?

for testnum=1:100
    filesavepath=['H:\Desktop\0208\' num2str(testnum) '_sen'];
    load(fullfile([filesavepath '\0208_' num2str(testnum) '_sen_avg_3.mat']),'matrix_avg');
    eval(sprintf('matrix_%g=matrix_avg;',testnum));
end

matrix=cat(2,matrix_1,matrix_2,matrix_3,matrix_4,matrix_5,matrix_6,matrix_7,matrix_8,matrix_9,matrix_10,matrix_11,matrix_12);

I am trying to concentrate 100 matrix for instance. I know how to load them 100 times at different folder, but how to make my last line

matrix=cat(2,matrix_1,matrix_2,.....matrix_99,matrix_100);

Thank you!

[Geoff Hayes]

Tsuwei - are all of your matrices of the same dimension? If not, then you could use a cell array to store all of these matrices.

myMatrices = cell(100,1);
for testnum=1:100
    filesavepath=['H:\Desktop\0208\' num2str(testnum) '_sen'];
    load(fullfile([filesavepath '\0208_' num2str(testnum) '_sen_avg_3.mat']),'matrix_avg');
    myMatrices{testNum} = matrix_avg;
end

If they are all of the same dimension then you should be able to create a single matrix that is sized appropriately.

In either case, try to avoid dynamically creating matrices with eval. This can lead to errors and has been discussed elsewhere in this forum.

Answer 1

[Stephen23]

Your approach is entirely in the wrong direction: using numbered variables is a sign that you are doing something wrong with your data/code design. Read this to know some of the reasons why:

https://www.mathworks.com/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval

The simpler alternative is to load the file data into an output variable (which is a structure), then your task is trivially easy (and much more efficient):

N = 100;
C = cell(1,N);
for k = 1:N
    F = fullfile(...);
    S = load(F,'matrix_avg');
    C{k} = S.matrix_avg;
end
M = cat(2,C{:})

See also:

https://www.mathworks.com/help/matlab/matlab_prog/comma-separated-lists.html

https://www.mathworks.com/matlabcentral/answers/320713-how-to-operate-on-comma-separated-lists