How to plot multiple plot in the same figure inside for-loop

Hi,

I have data of 15 participants. In my for loop, I import data for each participant and I calculate some values (like speed, acceleration, and so on).

I would like to plot "speed to time" figure for each participant in the same figure BUT I don't keep in an unique matrix all the variables from participant (i.e at each loop my variable timerLog and speedz were removed).

I can't share my code because I load my data from confidential folder but I could simulate what I've done :

% Data from Participant 1
timerLog=rand([5 1]); 
speedz=rand([5 1]); 

% Plot for Participant 1
Fig=figure;
hold on 
plot(timerLog,speedz);
xlabel('Time')
legend('location','southeast')
title ('Speed z')
axis tight    

% Next loop import data from Participant 2
timerLog=rand([5 1]); 
speedz=rand([5 1]); 

% Plot for Participant 2
Fig=figure;
hold on 
plot(timerLog,speedz);
xlabel('Time')
legend('location','southeast')
title ('Speed z')
axis tight  

%% I would like to have Plot for Participant 2 in the same figure than Participant 1

Thank you very much for your help,

Anne-Laure

[fred ssemwogerere]

Hello, is your data for the different participants stored in different files?

If so, you can make use of "fileDatastore", from which you can read the contents of different files in a loop, while plotting the results on the same axes. 'figure' should be initiated at the beginning of the loop, and 'hold on' at the end of the loop for plots to appear on the same axes.

Answer 1

[Jakob B. Nielsen]

If hold on is used, matlab will add plot commands to the active axes (or active figure, if you will), unless you specify otherwise. If hold off, it will replace the graphics. So in order to achieve what you want, simply initialise a single figure outside of your loop, and then set hold on like you also do. Then reference that figure for all your plots.

Fig=axes; 
hold on %the key. 

% Data from Participant 1
timerLog=rand([5 1]); 
speedz=rand([5 1]); 
% Plot for Participant 1
plot(Fig,timerLog,speedz); 
xlabel('Time')
legend('location','southeast')
title ('Speed z')
axis tight    

% Next loop import data from Participant 2
timerLog=rand([5 1]); 
speedz=rand([5 1]); 
% Plot for Participant 2 
plot(Fig,timerLog,speedz); 
xlabel('Time')
legend('location','southeast')
title ('Speed z')
axis tight

[Anne-Laure GUINET]

Thanks for your response but I have this error :

Error using plot
Line cannot be a child of Figure.

[Jakob B. Nielsen]

Can you post just the lines of code from your script, where this error comes from? Otherwise it is very difficult to say what the problem is.

[Anne-Laure GUINET]

Fig=figure; 
% Data from Participant 1
timerLog=rand([5 1]); 
speedz=rand([5 1]); 
% Plot for Participant 1
plot(Fig,timerLog,speedz); 
xlabel('Time')
legend('location','southeast')
title ('Speed z')
axis tight    
% Next loop import data from Participant 2
timerLog=rand([5 1]); 
speedz=rand([5 1]); 
% Plot for Participant 2
plot(Fig,timerLog,speedz); 
xlabel('Time')
legend('location','southeast')
title ('Speed z')
axis tight 

report error :

Error using plot
Line cannot be a child of Figure.

Error in test (line 30)
plot(Fig,timerLog,speedz);
 

Thanks,

AL

[Jakob B. Nielsen]

I slipped into an old mistake, it seems. It should be Fig=axes; and not Fig=figure;

[Anne-Laure GUINET]

Thanks, but it doesn't solve my problem.

It creates one figure (that what I want) but this fig concerns only the last participant.

I would like that datas from all participants are in the same fig. Perhaps it's not possible ... except if I create matrix that contains alle the datas...

[Jakob B. Nielsen]

Have you remembered the hold on? I edited the code in my first post to remove all the unneeded stuff. When I run it, it gives two plots in one figure just fine :)

[Anne-Laure GUINET]

It works !

Thank a lot Jakob !