MATLAB: How long does Hold on; last

figuregraphplot

I'm trying to plot a couple of graphs, but each refresh and rerun I do, the graph doesn't seem to be updating. Sometimes it does update but the old plots remain and the new plots get attached to it. Is it because of hold on;? Does it last beyond the script?

This is my code:

LabResponse = csvread('scope_0.csv', 2, 0);
LabResponse(:,1) = LabResponse(:,1) + 0.0015;
t = linspace(0, 1, 10000);
y = 1-exp(- t ./ (1000 * 10^(-6)));
plot(t,y); hold on;
plot(LabResponse(:,1), LabResponse(:,3));
xlabel('t');
ylabel('y');
axis([0 0.01 0 1])

Best Answer

Same answer as what Walter says, with the additional examples of when you call "hold off" or "cla".

"hold" is off by default. If you put hold on then "the old plots remain and the new plots get attached to it" is what you'll get. If you don't want that, then call "hold off" or "cla".

An even more drastic way to initialize the axes control is:

cla reset;

Nothing (no old plots or axes settings) should remain after you call that.

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MATLAB: Is there a quick way to shift real data points

"delayedT" variable in the above MATLAB script can have decimal values, and if you try to use it for indexing with "LabResponse" variable, MATLAB will throw the "Subscript indices must either be real positive integers or logicals." error.

You may find the following code to be useful for achieving what you are trying to do:

if true
  data = rand(1,10);
  time = 1:10;
  LabResponse = [time', data']; 
  shift = 2; %setting the shift to two time
  output = LabResponse(1:length(LabResponse)-shift, 2) - LabResponse(shift+1:length(LabResponse),2)
end

As you can see from the "output" variable, its length is 8 (total length - shift = 8) and also, output(1) = data(1) - data(1+shift). I hope this helps.

MATLAB: Only plotting on the last of three axes

Each axes has its own plot function. What does that mean?

If a figure has several axes, that means you used subplot to create the axis. You need to save the handle of these axis in order to replot in them:

figure;
hax(1) = subplot(1, 3, 1);  %save handle of 1st axis
plot(sin(linspace(0, 2*pi, 200)));
hax(2) = subplot(1, 3, 2);  %save handle of 2nd axis
plot(sqrt(linspace(0, 5, 200)));
hax(3) = subplot(1, 3, 3);  %save handle of 3rd axis
plot(log(linspace(0, 5 , 200)));

To replot in all axis

plot(hax(1), tan(linspace(0, 2*pi, 200)));  %plot in first axis
plot(hax(2), linspace(0, 5, 200).^2);       %plot in second axis
plot(hax(3), exp(linspace(0, 5, 200)));     %plot in 3rd axis

Alternatively, if you don't want to store the axis, you can reissue the subplot command:

subplot(1, 1, 1);  %replot in first axis
plot(cos(linspace(0, 2*pi, 200)));
subplot(1, 1, 2);   %replot in second axis
plot(linspace(0, 5, 200));
subplot(1, 1, 2);   %replot in 3rd axis

Best Answer

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MATLAB: Is there a quick way to shift real data points

MATLAB: Only plotting on the last of three axes

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