# How do I combine multiple plots in a for loop?

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Christopher on 18 Oct 2013
Commented: 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

Azzi Abdelmalek on 18 Oct 2013
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.

Jonathan LeSage on 18 Oct 2013
Edited: MathWorks Support Team on 27 Nov 2018
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

Show 1 older comment
Jonathan LeSage on 18 Oct 2013
Is the colormap method I suggested in my edit what you are looking for?
Christopher on 21 Oct 2013
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 :/

dpb on 18 Oct 2013
hold on
after first.

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
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);
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

ang yong qin on 16 Mar 2017
Maybe you can store the data in a matrix first before plotting the points all together.

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