Save matrices of a loop iteration in one matrix - matlab

Question

I have a loop that makes a 100x10 matrix in every iteration, i want to save all the matrices of this loop in one matrix. assuming that i have a loop with 5 iterations, i want to have a 500x10 matrix in the end (after appending all the 5 matrices of the loop).
for ii = 1:numfiles
str = fullfile(PathName,FileName{ii});
file_id = fopen(str);
data = fread (file_id)';
....
s = zeros (100, 10);
%doing some stuffs
save('s_all', 's','-append');
end
I have used save('s_all', 's','-append');
but it doesn't append the matrices. How can i do that?

Answer 1

As you can read in the document:
save(filename,variables,'-append') adds new variables to an existing file. If a variable already exists in a MAT-file, then save overwrites it with the value in the workspace.
Therefore, save just adds a variable at the end of the .mat file, not to add at the end of a variable inside the .mat file.
Solution 1:
To write matrix into the file it would be better using dlmwrite likes the following:
dlmwrite(filename,s,'-append');
You can find more details here.
In a complete case you can do:
filename = 's_all.csv';
for ii = 1:numfiles
str = fullfile(PathName,FileName{ii});
file_id = fopen(str);
data = fread (file_id)';
% ...
s = zeros (100, 10);
%doing some stuffs
dlmwrite(filename,s,'-append');
end
Solution 2:
The other solution is each time load the specified matrix, then attach the matrices into it, and then append to the file.
filename = 'file.mat';
% suppose originMatrix is an empty matrix or a matrix with columns size 10
for ii = 1:numfiles
load(filename,'originMatrix');
s = zeros (100, 10);
%doing some stuffs
originMatrix = [originMatrix; s];
save(filename,'originMatrix','-append');
end