Unable to process the data of a text file from a series of subfolders to get the required image.

I am trying to plot a power spectral density map from FFT calculations. I can read all tables from a series of folders. But I failed to get the required plot. The image showed the results of only the first table. Could you please look into the following code and help me out?

allTables = dir('**/table.txt');

for index = 1:numel(allTables)
    thisFolder = allTables(index).folder;
    inFile = fullfile(thisFolder, allTables(index).name);
    A = readmatrix(inFile);
    % do stuff ...
    
end

[Voss]

Hard to say more without knowing what the required plot looks like or having some files to run with, but maybe check that I here is non-empty for index > 1

I = find(A(:,11)==B);

[Jan]

"The image showed the results of only the first table." - why do you assume this? matrixplot is filled with the data from all files.

matrixplot=zeros(20001,19);

Where do the 20001 and 19 come from?

[Sateesh Kandukuri]

Dear Voss and Jan, the final plot should be like a below image.

I am attaching three table.txt files for the reference.

No, matrixplot=zeros(20001,19); is not filled with all the columns. The reason might be that the defined value of B is not exactly equal to the value in the 11th column of the table. In that case which logical expression is useful to define?

[Voss]

"The reason might be that the defined value of B is not exactly equal to the value in the 11th column of the table."

Exactly. Maybe use:

I = find(abs(A(:,11)-B) < Bstep/2);

[Sateesh Kandukuri]

Dear Voss, your suggestion is working, and the matrixplot is filled with all columns. But still, the output image is coming like before. I didn't understand why imagesc was plotting only the first coulmn.

[Jan]

imagesc does exactly what it is instructed to do. If it plots a part of the data only, its inputs contains a part of the data only.

[Sateesh Kandukuri]

Dear Jan, the problem is with the condtion I = find(abs(A(:,11)-B) < Bstep/2);. the value in the 11th column of the table is almost constant. It is approximately equal to defined B. The table from the second folder has an 11th-column value is 0.0040000007, and the last folder table has 0.07200002. If I use the condition I = find(A(:,11)==B); all columns of the matrix were not filled. Can you please help me out? I am attaching tables from three consecutive folders for your reference.

[Sateesh Kandukuri]

I solved the problem. Thank you so much for your suggestions.