# Add second y axis for a single data

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Gunay Gazaloglu on 27 Oct 2022
Commented: Gunay Gazaloglu on 27 Oct 2022
I have a problem adding a second y-axis; all solutions point out that I need another data set to have a second y-axis. However, I want to have two y-axis for a single point while the x-axis is the same.
For instance;
point=(3,6), and I want to show that on the right y-axis side, the point (3,6) has a 0.5 value, so the general notation could be as (x,y1,y2)=(3,6,0.5)
first data
For example;
x=[3,5,6,8,11]
y1=[6,7,9,14,17]
I want right y axis to be
y2=[0.5,2,5,7,11]
.
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Gunay Gazaloglu on 27 Oct 2022
Edited: Gunay Gazaloglu on 27 Oct 2022
You have a single point which has two dimesions (x and y) or (x,y)
x (horizontal axis)
y(vertical axis)
Then (3,6) is a point on that graph
after that I simply ask to have another y axis at the right side and .So your existing point (3,6) will have a value also at the right y axis.
I hope it is more understandable for you now.This is simplest way that ı can explain it...
Torsten on 27 Oct 2022
I think what you need is plot3, not a second y-axis.

Alberto Cuadra Lara on 27 Oct 2022
Hello Gunay,
Use yyaxis, here is a simple example.
Best,
Alberto
x = [3,5,6,8,11];
y1 = [6,7,9,14,17];
y2 = [0.5,2,5,7,11];
hold on; axis tight
plot(x, y1);
yyaxis right;
plot(x, y2);
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Alberto Cuadra Lara on 27 Oct 2022
Edited: Alberto Cuadra Lara on 27 Oct 2022
Hello Gunay,
If you want a line with data that is not proportional to each other, i.e., different scales, you will need to set a piecewise scale distribution. This can be done, for example changing yticks values and yticklabels.
% Data
x = [3,5,6,8,11];
y1 = [6,7,9,14,17];
y2 = [0.5,2,5,7,11];
% Plot configuration
colororder({'k','k'})
hold on; axis tight
% Plot (left)
plot(x, y1);
% Plot (right)
yyaxis right;
plot(x, y1);
% Change yticks (right)
set(gca, 'YTick', y1, 'YTickLabel', y2)
Gunay Gazaloglu on 27 Oct 2022
Thank you so much!