Getting an indexing error

I am getting this error and I don't know why.

Index in position 1 is invalid. Array indices must be positive integers or logical values.

This is the line I am getting it for:

plot(EEG.times,squeeze(EEG.data(channel_index,:,:)),'y')

I attached the data set that can be loaded to see what is going on.

I tried to attach the data file, but it is too large; even when compressed. The data file is sampleEEGdata.mat and can be found in this code downloaded from this link http://mikexcohen.com/book/AnalyzingNeuralTimeSeriesData_MatlabCode.zip

Answer 1

[Star Strider]

In MATLAB, indices must be integers greater than 0.

This illustrates a way to get some of the data and plot it —

Uz = unzip('http://mikexcohen.com/book/AnalyzingNeuralTimeSeriesData_MatlabCode.zip')

Uz = 1×57 cell array
    {'code/accumbens_eeg.mat'}    {'code/amsterdam.bmp'}    {'code/armorf.m'}    {'code/chapter02.m'}    {'code/chapter04_datafile.txt'}    {'code/chapter04_excel_data.xls'}    {'code/chapter04_headache_data.txt'}    {'code/chapter04a.m'}    {'code/chapter04b.m'}    {'code/chapter04c.m'}    {'code/chapter05.m'}    {'code/chapter06.m'}    {'code/chapter09.m'}    {'code/chapter10.m'}    {'code/chapter11.m'}    {'code/chapter12.m'}    {'code/chapter13.m'}    {'code/chapter14.m'}    {'code/chapter15.m'}    {'code/chapter16.m'}    {'code/chapter17.m'}    {'code/chapter18.m'}    {'code/chapter19.m'}    {'code/chapter20.m'}    {'code/chapter22.m'}    {'code/chapter23.m'}    {'code/chapter25.m'}    {'code/chapter26.m'}    {'code/chapter27.m'}    {'code/chapter28.m'}    {'code/chapter29.m'}    {'code/chapter30.m'}    {'code/chapter31.m'}    {'code/chapter33.m'}    {'code/chapter34.m'}    {'code/cover_art.m'}    {'code/data_output_SPSS_format.txt'}    {'code/data_written_from_matlab.txt'}    {'code/data2psiX.m'}    {'code/emdx.m'}    {'code/entropyx.m'}    {'code/erpviewerx.fig'}    {'code/erpviewerx.m'}    {'code/fdr.m'}    {'code/figure34_3_data.mat'}    {'code/frequency_sliding_and_median_filter.m'}    {'code/interpolate_nola.m'}    {'code/interpolate_perrinX.m'}    {'code/laplacian_nola.m'}    {'code/laplacian_perrinX.m'}    {'code/mutualinformationx.m'}    {'code/my_matlab_variables.mat'}    {'code/pathlength.m'}    {'code/sampleEEGdata.mat'}    {'code/solutions2exercises.pdf'}    {'code/tfviewerx.fig'}    {'code/tfviewerx.m'}

% n = strcmp(Uz{:},'sampleEEGdata')
D1 = load(Uz{54});
EEG = D1.EEG

EEG = struct with fields:
             setname: 'EEG sample dataset'
            filename: ''
            filepath: ''
             subject: ''
               group: ''
           condition: ''
             session: []
            comments: [4×63 char]
              nbchan: 64
              trials: 99
                pnts: 640
               srate: 256
                xmin: -1
                xmax: 1.4961
               times: [1×640 double]
                data: [64×640×99 single]
              icaact: []
             icawinv: []
           icasphere: []
          icaweights: []
         icachansind: []
            chanlocs: [1×64 struct]
          urchanlocs: []
            chaninfo: [1×1 struct]
                 ref: [-67 -68]
               event: [1×311 struct]
             urevent: [1×3009 struct]
    eventdescription: {''  ''  ''  ''  ''}
               epoch: [1×99 struct]
    epochdescription: {}
              reject: [1×1 struct]
               stats: [1×1 struct]
            specdata: []
          specicaact: []
          splinefile: ''
       icasplinefile: []
              dipfit: []
             history: '↵pop_eegplot( EEG, 1, 1, 1);↵EEG.setname='TheNewWave';↵EEG = pop_rejepoch( EEG, find(EEG.reject.rejglobal), 0);↵EEG = eeg_checkset( EEG );'
               saved: 'no'
                 etc: [1×1 struct]
             spedata: []

times = EEG.times;
data = EEG.data;
chans = EEG.chanlocs;

channel_index = 1:4;

figure
for k = 1:numel(channel_index)
    subplot(2,2,k)
    plot(EEG.times,squeeze(EEG.data(channel_index(k),:,:)),'b')
    title(sprintf('Channel %s',EEG.chanlocs(k).labels))
    xlabel('Time')
    ylabel('Amplitude')
    grid
end
sgtitle('First Four Channels')

.

[Ryan Griffith]

Thanks!

[Star Strider]

As always, my pleasure!