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How do I combine multiple plots in a for loop?

Asked by Christopher on 18 Oct 2013
Latest activity Commented on by Rik
on 11 Jun 2019
Hello all,
I am trying to plot within a for loop, but it only plots the last value, as it's overwritting previous values. My code look like the following:
BLOCK = 5x1 cell array
TIME = 5x1 cell array
for i=length(BLOCK)
plot(TIME(i),BLOCK(i))
end
Not sure how to get this, so it doesn't overwrite previous values. Thank you

  1 Comment

Christopher commented
I am trying to change the color for each i iteration though. This works, but gives me the same color plot for every iteration.

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3 Answers

Answer by Jonathan LeSage on 18 Oct 2013
Edited by MathWorks Support Team on 27 Nov 2018
 Accepted Answer

Add “hold on” prior to your for-loop.
Adding a "hold on" command means that anything that you plot will not clear the existing graph, but just plot on top of what is already there. You can turn off this functionality with the "hold off" command.
for k = 1:length(BLOCK)
plot(TIME(k),BLOCK(k))
if k == 1
hold on
end
end
hold off

  4 Comments

Show 1 older comment
Is the colormap method I suggested in my edit what you are looking for?
Thank you Jonathan, that is exactly what I was looking to do. I have accepted your answer. Thanks to everyone else for there responses as well.
Rik
on 11 Jun 2019
Comment mistakenly posted as flag by AISWARYA LAKSHMI:
This code did not work for me! Only an empty plot screen appears :/

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Answer by dpb
on 18 Oct 2013

hold on
after first.

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Answer by Hem Zaveri on 1 Nov 2014

I needed to plot graph of frames Vs pixel difference. And the plot was supposed to be inside the for loop. So after seeing this answer I solved one issue, that i update the graph using update. But i want all the points to be connected. Can you help me with it ?
Here is my code
for f = startingFrame+1 : finalFrame
frame = aviread(inFile, f);
i2 = frame.cdata; %cdata — The image data stored as a matrix of uint8 values. The dimensions of F.cdata are height-by-width-by-3.
ig2 = rgb2gray(i2);
[c2,n2] = imhist(ig2);
c2=c2/size(ig2,1)/size(ig2,2);
d = pdist2(c1',c2','cityblock');
if (d > 0.2150) %%change the threshold
c1 = c2;
m = im2frame(i2);
mov = addframe(mov,m);
pause(1/FPS);
end
disp(d);
hold on;
axis([1 95 0.16 0.26]);
plot(f,d,'--rs','LineWidth',2,...
'MarkerEdgeColor','k',...
'MarkerFaceColor','g',...
'MarkerSize',10);
end
f = frame, d = pixel difference which lies between 0.16 - 0.26 </matlabcentral/answers/uploaded_files/20313/asd.PNG>

  1 Comment

Maybe you can store the data in a matrix first before plotting the points all together.

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