MATLAB: How to clear array in between multiple plots in for loop

clear arraysfor loopplot

Hi everyone,
I'm having some trouble doing multiple plots in a for loop. The arrays I use for my plot, stores data from previous iteration, messing up the plots.
Based on a .csv file containing data from 20+ devices, I wan't to seperate the data unique to each device and plot it. I do this as follows.
 fid = fopen('Regular_events_24_10.csv');
 readData = textscan(fid, '%f %s %q %f %f %f %s %s %s %s %s %s %s %s %s %s', 'Headerlines', 1, 'Delimiter', ',');
 device_name = ["device_name1", "device_name2"....]
 for u = 1:length(device_name)
    k = 1;
    for n = 1:length(readData{:,2})
        if strcmp(strcat('"',device_name(u),'"'),readData{1,2} (n,1))
            %disp(n);
            for i = 1:16
                temp_array{1,i} (k,1) = (readData{1,i} (n,1));
            end
            k = k + 1;
            %disp(k);
        end
    end
 device_time = temp_array{1,3} (:,1);
 state = temp_array{1,4} (:,1);
 progress = temp_array{1,6} (:,1);
 desk_setting = temp_array{1,7} (:,1);
 user_presence = temp_array{1,8} (:,1);
 desk_height = temp_array{1,9} (:,1);
 IR_obj = temp_array{1,12} (:,1);
 figure('rend','painters','pos',[150 60 1100 750])
 subplot(2,1,1);
 hold on
 title(device_title(u));
 plot(dateAndTimeSerial,desk_height, 'r');
 plot(dateAndTimeSerial,progress, 'k');
 plot(dateAndTimeSerial,desk_setting_int, 'b');
 datetick('x','HHMM');
 legend('desk height','progress','desk setting int', 'Location','west');
 hold off
 subplot(2,1,2);
 hold on
 plot(dateAndTimeSerial,IR_obj, 'r');
 plot(dateAndTimeSerial,user_presence_int, 'k');
 plot(dateAndTimeSerial,state, 'b');
 datetick('x','HHMM');
 legend('IR obj', 'user presence int', 'state', 'Location','west');
 hold off
 end
I have omitted some of the code, where I typecast some of the data and so on. Should be irrelevant for my question.
I have tried to clear and overwrite all arrays at the end of the for loop, but I doesn't help anything.
Hope you can help me out,
Best regards Mads
For reference, this is what a failed plot looks like.

Best Answer

The immediate problem is that indeed you fail to clear your temp_array at the beginning of each step of your u loop. Simply fixed with
for u = 1:length(device_name)
   temp_array = {};
   %...


would fix that. Saying that, your code is very inefficient. You do need to learn to vectorise your code rather than looping over everything. Your n loop can be easily replaced. The i loop as well with a bit more effort. As a bonus, it wouldn't require to clear the temp_array as it would recreate a brand new one each time:
for u = 1:numel(device_name) 
  isdevice = strcmp(['"', device_name(u), '"'], readData{2});  %no need to index you can compare the whole column at once
  temp_array = cellfun(@(col) col(isdevice), readdata, 'UniformOutput', false);
  %...
However, your life would be a lot easier if you used readtable to import your data. A table is a lot easier to manipulate that a cell array of columns.
readdata = readtable('Regular_events_24_10.csv');  
%import all done however we can clean up some columns
readdata.device_time = datetime(readdata.device_time);
readdata.desk_setting = strcmp(readata.desk_setting, 'True');
readdata.desk_setting = strcmp(readata.desk_setting, 'False');
%note that the above can be done by readtable if you override the import options. See the doc
Looping over the devices is trivial
for device = unique(readdata.device_id)'
  device_name = device{1};
  filtered_table = readdata(strcmp(readdata.device_id, device_name), :);
  figure('rend','painters','pos',[150 60 1100 750]);
  subplot(2,1,1);
  hold on
  title(device_name);
  plot(filtered_table.device_time, filtered_table.desk_height, 'r');
  plot(filtered_table.device_time, filtered_table.progress, 'k');
  plot(filtered_table.device_time, filtered_table.desk_setting, 'b');
  datetick('x','HHMM');
  legend('desk height','progress','desk setting', 'Location','west');
  hold off
  %...
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