MATLAB: How to concentrate matrix 100 times

Question

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!

Answer 1

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