Help with looping through columns from .csv-file and writing data to .xlsx-file

I have written a script that is supposed to do some calculations on a .csv-file that the user has chosen, and write the results to different columns in an .xlsx-file.

I have a loop that runs through different letters for a variable that decides which column in the .xlsx should have the written data - this works. The part that doesn't is the loop with an array, rfd200left(k), that calculates a number on 5 different columns in the .csv-file. What I get in the columns of the .xlsx is the same number on all 5 cells (I get the last calculated number of the loop. I tried moving around almost everything, but I can't find the flaw. The code is below, and the .csv-file is attached for context. Let me know if any additional information is needed.

This first part is a browse-button, that let's the user browse for a csv-file to be read.

function vaelgPushed(app, event)
            %Browse files
            [filename, pathname] = uigetfile('*.csv');
            app.UIFigure.Visible = 'off';
            app.UIFigure.Visible = 'on';
            app.fullpathname = strcat(pathname, filename);
            app.valgt.Value = app.fullpathname;
            
            % Read csv-file
            app.rfdtest = csvread(app.fullpathname, 8, 1);
end

The next part is the button that analyzes the csv-file, and writes calculated data to an excel-document. This is where my loop is doing something wrong at the "writetable"-part:

function analyserPushed(app, event)

rfdtest = app.rfdtest; 
fullpathname = app.fullpathname;
threshold = 1.5;
newton = 4.44822162;


for k = 1 : 5
    left = rfdtest(:, k);
        if left(1)>0
            left=[0;left]  % If the first item in a column is not zero, add zero.
        end
        
for letter='E':'I'
    column = [letter,'2']
    
% Variables for calculations
indexoverLeft = find(left>threshold,1);
P1Left = left(indexoverLeft,1);
   
prethreshLeft = indexoverLeft-1;
P2Left = left(prethreshLeft+21);

% -- Find RFD 200 ms [Pounds/sek]
    if (P2Left-P1Left)/0.2 > 0
            rfd200left(k) = (P2Left-P1Left)/0.2;
            T = table(rfd200left(k));
            writetable(T,'rfd_skitse_kopi.xlsx', 'range', column, 'WriteVariableNames', false)
    end
    
end
end
end

[Bob Thompson]

I'm sorry, I didn't run your code specificially, but in looking over what you posted does T have more than one value, and are those values unique?

[Mikkel Eskildsen]

T changes on every iteration to the the calculated rfd200left value, from the specific column of that iteration. So on every iteration, a new value is written to the .xlsx-document (which is why I use the Letter loop, for changing the target cell in every iteration)

[Bob Thompson]

It is the presence of the internal letter loop that is causing your problem. You are writing all five cells for each time you run the k loop. I think you could solve your problem by removing the internal loop, turning T into a matrix, and printing all of T at one time after the k loop.

[Mikkel Eskildsen]

Ah yes of course. Worked immediately. You have my vote if you want to make this an answer.

Thank you!

Answer 1

[Bob Thompson]

It is the presence of the internal letter loop that is causing your problem. You are writing all five cells for each time you run the k loop. I think you could solve your problem by removing the internal loop, turning T into a matrix, and printing all of T at one time after the k loop.