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How to set a legend with a label for two or more lines?

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Hello,
In the graphic legend I want to share the same label for two or more lines.
For example, I have two (or more) pair of data
x = linspace(0,0.5);
for i = 1:3
y1(i,:) = x.^2 + i;
y2(i,:) = (2*x).^2 + i;
end
My plot instructions are
hold on
plot(x,y1,'-')
set(gca,'ColorOrderIndex',1)
plot(x,y2,'--')
legend({'label 1','label 2','label 3'})
I want that the first curves of y1 and y2 share the label “label 1” and so on for the second and the thirds lines, “label 2” and “label 3”, respectively. Something like this
figure2.png
Thanks in advance for the answers.
  10 Comments
Adam Danz
Adam Danz on 7 Feb 2020
I understand. Walter pointed you to a function on the file exchange that might be helpful in building a custom legend.

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Accepted Answer

Jeremy
Jeremy on 7 Feb 2020
This isn't a particularly elegant solution, but I think it does what you want.
x = linspace(0,0.5);
for i = 1:3
y1(i,:) = x.^2 + i;
y2(i,:) = (2*x).^2 + i;
end
hold on
plot(x,y1,'-')
set(gca,'ColorOrderIndex',1)
plot(x,y2,'--')
[lh, labelhandles] = legend({'label 1','label 2','label 3'});
labelhandles(5).LineStyle = '--';
labelhandles(4).YData = [0.83 0.83];
labelhandles(5).XData = [0.0460 0.5057]; labelhandles(5).YData = [0.760 0.760];
This will only update one of the legend entries, I trust you can extend this solution to the others. You could also choose a labelhandles variable with a shorter name to make it look a little neater, if you wanted.
Your YData property can be tweaked until you are happy with the appearance.
plot_legend.png
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