how to plot different range of files on one graph using hold on

i have 63 .mat files that contain cells of data. i am dividing the .mat files into three parts so that each file is plotted correspondingly on the same graph from another set. that is, file 1 in the first, second third set are plotted on the same graph using hold on and the same for file 2 and so on. Although, i have not included the plot command, i am still trying to see how the code looks like by dividing the files into two sets.

startIndex = 1;
endIndex = 3;
startIndex1 = 4;
endIndex1 = 6;
count1 = 0;
count2 = 0;
filelist = dir('C:\Users\shedr\Downloads\tec data\2017\DOBUM\ttr\ttr1\tt4\*.mat');
% first set of files
for fileidx = startIndex:endIndex 
    count1 = count1+1;
    
    spectrum = load(filelist(fileidx).name);
    C = spectrum.B
    % second set of files
    for fileidx1 = startIndex1:endIndex1
        count2 = count2+1;
        if count2 == count1
            
            spectrum1 = load(filelist(fileidx1).name);
            C1 = spectrum.B
            
        end
    end
    % but the output is not favourable.

Answer 1

[Walter Roberson]

startIndex = 1;
endIndex = 3;
startIndex1 = 4;
endIndex1 = 6;
count1 = 0;
filelist = dir('C:\Users\shedr\Downloads\tec data\2017\DOBUM\ttr\ttr1\tt4\*.mat');
% first set of files
for fileidx = startIndex:endIndex 
    count1 = count1+1;
    count2 = 0;
    spectrum = load( fullfile(filelist(fileidx).folder, filelist(fileidx).name));
    C = spectrum.B;
    % second set of files
    fileidx1 = startIndex1 + (fileidx - startIndex);
    spectrum1 = load(fullfile(filelist(fileidx1).folder, filelist(fileidx1).name));
    C1 = spectrum.B;
    %do something with C and C1
    plot(C, 'displayname', filelist(fileidx).name);
    hold on
    plot(C1, 'displayname', filelist(fileidx1).name);
end
hold off
legend('show')

[shedrach]

Thank for your answer. C and C1 are outputting well but they are not plotting. When I try to plot, it gives me an error message: invalid data argument. Is there a solution to this?

[shedrach]

I think everything is ok now. I forgot I had to convert my file from cells to matrix. That was why it was telling me invalid data argument. Thanks.

[shedrach]

I just noticed that I am getting only the last plot. The first and second plots are not shown. Is there any solution?

[Walter Roberson]

Considering the "hold on" then if only the last plot is showing up, either you removed the "hold on" or else the data happens to be exactly overlaying the previous plot.

[shedrach]

yes the last plot is overlaying the first plot. The last plot is showing six legend instead of three with two line plots which is expected. I need the output to be three figures with two plots each. first plot; file1 from group1 and file1 from group2, second plot: file2 from group1 and file2 from group2 and so on. Thanks.

[Walter Roberson]

startIndex = 1;
endIndex = 3;
startIndex1 = 4;
endIndex1 = 6;
count1 = 0;
filelist = dir('C:\Users\shedr\Downloads\tec data\2017\DOBUM\ttr\ttr1\tt4\*.mat');
% first set of files
for fileidx = startIndex:endIndex 
    count1 = count1+1;
    count2 = 0;
    spectrum = load( fullfile(filelist(fileidx).folder, filelist(fileidx).name));
    C = spectrum.B;
    % second set of files
    fileidx1 = startIndex1 + (fileidx - startIndex);
    spectrum1 = load(fullfile(filelist(fileidx1).folder, filelist(fileidx1).name));
    C1 = spectrum.B;
    %do something with C and C1
    figure()
    tiledlayout()
    nexttile();
    plot(C, 'displayname', filelist(fileidx).name);
    legend('show')
    title(filelist(fileidx).name)
    nexttile();
    plot(C1, 'displayname', filelist(fileidx1).name);
    legend('show')
    title(filelist(fileidx1).name)
end

[shedrach]

Not really what i want. The plots are plotting on 2 subplots of for each iteration. Please, I want the two subplots to be on one plot, distinguished by colour codes, thereby having three figures with two plots on each for each iteration.

If not for the loop, this could have been done easily using the hold on. But using the hold on inside the for loop is really my problem. Thanks.

[Walter Roberson]

startIndex = 1;
endIndex = 3;
startIndex1 = 4;
endIndex1 = 6;
count1 = 0;
filelist = dir('C:\Users\shedr\Downloads\tec data\2017\DOBUM\ttr\ttr1\tt4\*.mat');
% first set of files
for fileidx = startIndex:endIndex 
    count1 = count1+1;
    count2 = 0;
    spectrum = load( fullfile(filelist(fileidx).folder, filelist(fileidx).name));
    C = spectrum.B;
    % second set of files
    fileidx1 = startIndex1 + (fileidx - startIndex);
    spectrum1 = load(fullfile(filelist(fileidx1).folder, filelist(fileidx1).name));
    C1 = spectrum.B;
    %do something with C and C1
    figure()
    plot(C, 'displayname', filelist(fileidx).name);
    hold on
    plot(C1, 'displayname', filelist(fileidx1).name);
    hold off
    legend('show')
end

[shedrach]

Thank you. This last one got it