save column values of different multiple .txt files without overwriting in a for loop.

yr = [1951:2018]';

for j = 1:size(A)

fil = importdata([folder, A(j).name]);

file = dlmread(fullfile(folder , A(j).name));

for i = 1:size(yr,1)

a = find(file(:,1)==yr(i));

M(i,1) = sum(file(a,4));

end

end

I imported all files using 'dir' ansd stored in A. The problem is that Only Last file is getting operated on.

[KALYAN ACHARJYA]

Are you want to write M(i,1) data in txt file?

[Angana Borah]

No. I want to bring the 4th column of all the files in the sructure to one data_array,M. Did you get my question? In the for loop, only the file file is getting read and sum of the column of only that file is calculated. Whereas, I want 4th column from all the files.

Answer 1

[KALYAN ACHARJYA]

I want to bring the 4th column of all the files in the sructure to one data_array,

1. Read the txt file one by one (As you mentioned you have done it sucessfully)
2. iter i=1
3. Extract the 4th column from i file
4. Save the column data in cell array
5. Repeat, iter 2

Step 3:

col_data{i}=writetable(column_data,['file_test',num2str(i),'.txt'])

[Angana Borah]

Thanks a lot. But I do not want to store column data from various files in different .txt files but want to input in the different columns of the same matrix if that is possible.