How to find the maximum values from each column 2 and 3 and find the corresponding values from column 1?

I have 543 .txt files with 3 columns. I need to find the maximum values for column 2 and 3 for each of these files and scatter plot the values. Then I have to find corresponding values from column 1 for those maximum values in Column 2 and 3 and again scatter plot those values. Please help. This is the code I wrote.

list=dir('*.txt'); 
for n=1:length(list)
    filename=list(n).name;
    filename_edit=strrep(filename,'.',';');
    part=textscan(filename_edit,'filename;%d;%d;%d;%d;%s');
    delimiterIn = ' ';
    A = importdata(filename,delimiterIn);
    Altitude = A(:,1);
    Digisonde = A(:,2);
    COSMIC = A(:,3);
    for i = 1:n
        if Altitude > 150,
        out1 = max(Digisonde);
        out2 = max(COSMIC);
        else 
        out3 = max(COSMIC);
        end
    end
    scatter(out1,out2,'filled')
    xlabel('Digisonde')
    ylabel('COSMIC')
end

[Jan]

I've formatted your code: Mark it with the mouse and press the "{} Code" button. Afterwards it is readable.

The actual problem seems to be in:

    Altitude = A(:,1);
    Digisonde = A(:,2);
    COSMIC = A(:,3);
    for i = 1:n
        if Altitude > 150,
          out1 = max(Digisonde);
          out2 = max(COSMIC);
        else 
          out3 = max(COSMIC);
        end
    end

Why do you insert a loop over n (the number of files) inside the loop over the files? Altitude is a vector, but the if command requires a scalar input. Therefore an if all(Altitude > 150) is performed internally. Is this wanted?

[SGMukherjee]

The values of out1 and out2 keep on being replaced by new values. But I need to scatter plot for all the maximum values of "COSMIC" and "Digisonde" from 543 files.

[Jan]

You overwrite all values in both loops and each iteration. The purpose of the inner loop "for i=1:n" is not clear, because it calculates the same data n times. If you want to store the values, store them. An example:

r = zeros(1, 100);
for k = 1:100
  r(k) = rand;
end

Now the elements of r are collected by storing each value in a new element of the vector r.

Answer 1

[Jan]

 find corresponding values from column 1 for those maximum values in
 Column 2 and 3

This would be:

   [out1, index1] = max(Digisonde);
   alt1           = Altitude(index1);
   [out2, index2] = max(COSMIC);
   alt2           = Altitude(index2);