How should I write a code that can realize if a text file is updated and the code updates my plot too?

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Sepehr Ariaei 2021-6-26

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回答： Sepehr Ariaei 2021-6-28

test_data.txt

I have a log file which is keep updating a message (text file attached). This message can somehow be plotted and I have done that (see below) but I don't know how to update my plot when the txt file is updated with a new line?

logfile = uigetfile
opt = detectImportOptions(logfile,'FileType','text','Delimiter',','); % setting import options
opt.VariableNames = {'LogType','RealTimeStamp','DataSet','ParticleTimeStamp','ForcedParticleFlag','TriggerIntensity','Channel2','Channel3','Channel4','Channel5','Channel6','Channel7','Channel8','Channel9','Channel10','Channel11','Channel12','Channel13','Channel14','Channel15','Channel16','Channel17','Channel18','Channel19','Channel20','Channel21','Channel22','Channel23','Channel24','Channel25','Channel26','Channel27','Channel28','Channel29','Channel30','Channel31','Channel32'};
opt.ExtraColumnsRule ='ignore';      % remove extra column
ImportLog = readtable(logfile,opt);   % import log file
ImportLog=ImportLog(~any(ismissing(ImportLog),2),:); % import only scattering data and remove other data
ChannelToAngle_T = PHIPS_ChannelToAngle(ImportLog);      % channel to angle table
ForcedTrigger = ChannelToAngle_T.ForcedParticleFlag; % forced trigger out of table
idx0 = find(ForcedTrigger == 0);                      % index of those lines that has forced trigger or not
idx1 = find(ForcedTrigger == 1);  
for i= 1:numel(idx0)
  
    Angle = 18:8:170;                            % Angles
    ASF = table2array(ChannelToAngle_T(idx0(end), end-19:end)); % Angular Scattering Function
    semilogy(Angle, ASF, 's-','MarkerFaceColor', 'w', 'LineWidth', 2, 'MarkerSize', 10) % plot
    hold on
    %semilogy(angle, ASF_2, 's--','MarkerFaceColor', 'w', 'LineWidth', 2, 'MarkerSize', 10)
    %semilogy(angle, ASF_3, 's--','MarkerFaceColor', 'w', 'LineWidth', 2, 'MarkerSize', 10)
    hold off
    grid on
    xlabel ('Scattering Angle')
    ylabel ('Scattering Intensity [cts]')
    ylim([0, 5000])
    ax = gca;
    ax.YAxis(1).Color = 'k'; % change color of LHS y-axis to black
    % ax.YAxis(2).Color = 'k'; % change color of RHS y-axis to black
    ax.FontSize = 14; 
    ax.FontWeight = 'bold';
    legend('Location', 'southeast')
%     
end

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Answer 1

Image Analyst 2021-6-26

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https://ww2.mathworks.cn/matlabcentral/answers/865780-how-should-i-write-a-code-that-can-realize-if-a-text-file-is-updated-and-the-code-updates-my-plot-t#answer_734130

You could periodically check the date of the file with dir() (in a for loop or with a timer) and if the file date changed from the last time you checked it, update your plot.

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Walter Roberson 2021-6-27

在 MATLAB Online 中打开

how_long_to_wait = 5;
[logfile, logdir] = uigetfile;
if ~ischar(logfile); return; end     %user cancel
logfile = fullfile(logdir, logfile);
opt = detectImportOptions(logfile,'FileType','text','Delimiter',','); % setting import options
opt.VariableNames = {'LogType','RealTimeStamp','DataSet','ParticleTimeStamp','ForcedParticleFlag','TriggerIntensity','Channel2','Channel3','Channel4','Channel5','Channel6','Channel7','Channel8','Channel9','Channel10','Channel11','Channel12','Channel13','Channel14','Channel15','Channel16','Channel17','Channel18','Channel19','Channel20','Channel21','Channel22','Channel23','Channel24','Channel25','Channel26','Channel27','Channel28','Channel29','Channel30','Channel31','Channel32'};
opt.ExtraColumnsRule ='ignore';      % remove extra column
ax = app.axes1;
cla(ax)
ax.YScale = 'log';
h = plot(nan, nan, 's-','MarkerFaceColor', 'w', 'LineWidth', 2, 'MarkerSize', 10);
oldsize = -inf;
while true
   FileInfo = dir(logfile);
   if FileInfo.bytes > oldsize
      oldsize = FileInfo.bytes;
      ImportLog = readtable(logfile,opt);   % import log file
      do some stuff
      h.XData = Angles; h.YData = ASF;
      drawnow();
   else
       pause(how_long_to_wait)
   end
end