Read multiple txt files and plot all in one graph

Hello,

I'm using the app designer for my project. My goal is to read multiple txt files and plot them all in one single graph so I can see if the data is similar or not.

I figured out how to do it with one file. But I'm struggeling with more files. The code I'm using for one file is listed down below (callback function of the "Read Data" button. In the uploaded picture you can see what I was trying to do.

I would like to press "Read Data" and choose multiple files, read them in so they will be shown in Column 1, Column 2, Column n... and one graph where all data will be shown.

While browsing through older threads, I found this link here: https://de.mathworks.com/matlabcentral/answers/443167-importing-multiple-txt-files-into-one-table

The problem I have is that I somehow can't figure out how to transfer it to my project especially because I don't need the delimited function and the fact that I have two columns.

I'd be really happy if someone can help or guide me through my problem.

function ReadDataButtonPushed(app, event)
    t ) readtable(uigetfile('*.txt'), 'Format', '%f %f');
    app.UITable.Data= t;
    t.Properties.VariableNames{1} = 'Time_s'; %Just in case I want to change the names
    t.Properties.VariableNames{2} = 'AI_V';
    app.UITable.ColumnName = t.Properties.VariableNames;
    x = table2array(t(:, "Time_s"));
    y = table2array(t(:, "AI_V"));
    plot(app.UIAxes,x,y);
end

Answer 1

[Sourabh Kondapaka]

Hi,

I have updated your callback function. When the first file is selected, as the “Data” property of “app.UITable” will be empty it will fill out both the columns.

For all subsequent files that are selected, they get appended to the “app.UITable” and the “app.UIAxes” is updated.

I had changed naming the "AI_V" column to be more specific from the file it has been imported from.

The names of columns that will be generated for "AI_V" column would be "AI_V_Sample1-Test1", "AI_V_Sample2-Test2" and "AI_V_Sample3-Test3".

% These are the properties that will be used in the "ReadDataPushed()" callback function. 
properties (Access = public)
        file; % File Name.
        path; % File Path.
        columnName; % Name of the column that will be specific to the imported file.
        x; % x-axis data to plot.
        y; % y-axis data to plot.
    end

function ReadDataPushed(app, event) 
            [app.file, app.path] = uigetfile('*.txt');
            t = readtable(fullfile(app.path, app.file), 'Format', '%f %f'); 
            
            if isempty(app.UITable.Data) 
                app.UITable.Data = t; 
                t.Properties.VariableNames{1} = 'Time_s';
                t.Properties.VariableNames{2} = ['AI_V' '_' app.file(1:end -4)]; 
                app.UITable.ColumnName = t.Properties.VariableNames; 
                
            else 
                app.columnName = ['AI_V' '_' app.file(1:end-4)]; 
                app.UITable.Data.(app.columnName) = t{:,2}; 
                app.UITable.ColumnName = [app.UITable.ColumnName; app.columnName]; 
            end 

            app.x = app.UITable.Data{:, 1}; 
            app.y = app.UITable.Data{:,2:end}; 
            plot(app.UIAxes, app.x, app.y);             

        end 

[Phi Kevin Ho]

Thank you very much! The code works good now. I had to add properties(Access = private) to enter file, path columnName. x and y because the properties (Access = public) isn't editable.

I figuered out two more issues...

I tried to add a legend so I can see which line belongs to which data. My idea was to add the line

legend(app.UIAxes, t.Properties.VariableNames{2})

It works fine for the first file but by adding another file it doesn't add another filename. Instead it shows something different.

The only function that is working by keeping updating the legend is

legend(app.UIAxes, app.UITable.ColumnName)

But the Problem is that the first line is being named by the first column and the second line by the second column.

The second issue is, that I get a problem if the other files don't have the same amount of rows like the first one. Do you have any advice so I can try to fix that problem?