MATLAB: Load and do operations on multiple file in a loop

for looploopMATLABtext file

Hi,
I have my files named 'Us2asp_001.txt', 'Us2asp_002.txt, …….'Us2asp_00n.txt'.
I want to read the files and do similar operations in each of them.
I read about it and got to know that sprintf is a solution. However, the files are saved into a cell array and I am not sure how to do the further calculations.
I am rather new to matlab. Can you please help me with this?
I have attached the code which I want to write in a loop.
Thank you in advance.
Regards
Dipen
data1=readtable('Upasp2_001.txt');
data2=readtable('Upasp2_002.txt');
data3=readtable('Upasp2_003.txt');
%% Changing units
data1{:,2:end}=data1{:,2:end}*-1000;
data2{:,2:end}=data2{:,2:end}*-1000;
data3{:,2:end}=data3{:,2:end}*-1000;
%% Calculation
data1{:,7}=data1{:,3}+data1{:,5};
data1{:,8}=data1{:,4}+data1{:,6};
data1{:,9}=sqrt(data1{:,7}.^2+data1{:,8}.^2);
data1.Properties.VariableNames([7 8 9])={'Px','Py','Ptot'};
data2{:,7}=data2{:,3}+data2{:,5};
data2{:,8}=data2{:,4}+data2{:,6};
data2{:,9}=sqrt(data2{:,7}.^2+data2{:,8}.^2);
data2.Properties.VariableNames([7 8 9])={'Px','Py','Ptot'};
data3{:,7}=data3{:,3}+data3{:,5};
data3{:,8}=data3{:,4}+data3{:,6};
data3{:,9}=sqrt(data3{:,7}.^2+data3{:,8}.^2);
data3.Properties.VariableNames([7 8 9])={'Px','Py','Ptot'};
%% Plotting
figure
plot(data1.uxtop,data1.Ptot,data2.uxtop,data2.Ptot,data3.uxtop,data3.Ptot);
legend('Mesh 1','Mesh2','Mesh3');
title('Load displacement');
xlabel('ux (mm)');
ylabel('Total Load applied (P) kN');
xlim([0,10]);

Best Answer

Hi Dipen,
As far as I understand you want to read all the files in a specific folder with a for loop and do the calculations.
I wrote some code for you, you can check if it works correctly.
(Please don't forget to read comments.)
%% this part gives you the txt file name list in your folder
dirName = 'C:\Users\....\Desktop\NewFolder';   % folder path (please edit this as your own)
files = dir( fullfile(dirName,'*.txt') );   % list of all *.txt files
files = {files.name}';                   % file names
%pre allocation for legend for the plot
legendString = cell(1,numel(files));
%% for loop
for i = 1:numel(files) % for loop for each file
    % readtable
    data = readtable(files{i});
    % changing units
    data{:,2:end}=data{:,2:end}*-1000;
    % Calculation
    data{:,7}=data{:,3}+data{:,5};
    data{:,8}=data{:,4}+data{:,6};
    data{:,9}=sqrt(data{:,7}.^2+data{:,8}.^2);
    data.Properties.VariableNames([7 8 9])={'Px','Py','Ptot'};
    % plot
    figure;
    plot(data.uxtop,data.Ptot); % plots the ith file data 
    hold on; % holds the plot for the next loop
    legendString{i} = ['Mesh',sprintf('%d',i)]; % creates legend string as MeshX where X is a number
end % end for loop
%% legend,title,axis properties for plotted figure
legend(legendString);
title('Load displacement');
xlabel('ux (mm)');
ylabel('Total Load applied (P) kN');
xlim([0,10]);
ps. If you want to shorten your calculations section, please share an example data(txt) and desired output.
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