How to end loop after key is press
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Addison Collins
on 15 Jul 2021
Edited: Addison Collins
on 15 Jul 2021
Hello everyone,
I am attempting to make it so I can have as many iterations as I want in the for loop. I want to choose when I am done using ginput rather than relying on a preset number ("num" in the code below). This would mean running the loop until I press a key, after which the loop is exited. I have attached an image of the plot.
EDIT: I edited the code posted below to reflect my final script that works. If enter is pressed, ginput will not throw an error, and the loop will be exited. If another key is pressed, the loop will also stop. NOTE that when a different key other than 'ENTER' is used to break from the loop, an additional point will be plotted wherever the cursor is located. I am too lazy to fix this at the moment.
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/685378/image.png)
clc;clear;close all
rng default
xq = rand(500,1)*5;
yq = rand(500,1)*5;
f = figure;
j = 1;
plot(xq,yq,'b+'); hold on;
axis equal
while true
try % ginput(number) throws error when 'ENTER' is pressed
[xv(j), yv(j)] = ginput(1);
plot(xv(j),yv(j),'ro','MarkerFaceColor','r','MarkerSize',3)
if j > 1
plot(xv(j-1:j),yv(j-1:j),'LineWidth',2,'color','red') % polygon
end
j=j+1;
catch
break;
end
% In case something other than enter is pressed
if f.CurrentCharacter > 0
break;
end
end
in = inpolygon(xq,yq,xv,yv);
figure
plot(xv,yv,'LineWidth',2,'color','red') % polygon
axis equal
hold on
plot(xq(in),yq(in),'r+') % points inside
plot(xq(~in),yq(~in),'bo') % points outside
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Accepted Answer
Scott MacKenzie
on 15 Jul 2021
Edited: Scott MacKenzie
on 15 Jul 2021
Here's an arrangement I've used with good success in the past. The loop executes indefinitely until a key is pressed.
f = figure;
% other code
while true
% put your loop code here
if f.CurrentCharacter > 0
break;
end
end
5 Comments
Scott MacKenzie
on 15 Jul 2021
Edited: Scott MacKenzie
on 15 Jul 2021
I've deleted this comment, as I see in your next comment that you've now got things working just fine.
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