How can I add a second Y axis with a different scale in a plot in MATLAB 7.9 (R2009b)?

I create a plot and want to have two different Y scales to display two different units for the same data. For example, when I draw the following plot:

figure;

plot(1:10);

I want to add the second Y axis with the following limits:

 [20 25]

Answer 1

[MathWorks Support Team]

The following examples show how to add the second Y axis that ranges from 20 to 25:

1. Add the second Y axis manually:

% Plot function.

h = plot(1:10)

hold on

box off

% Create second Y axes on the right.

a2 = axes('YAxisLocation', 'Right')

% Hide second plot.

set(a2, 'color', 'none')

set(a2, 'XTick', [])

% Set scala for second Y.

set(a2, 'YLim', [20 25])

2. Use PLOTYY:

figure; 

[a,h1,h2]=plotyy(1:10, 1:10, 1:10, linspace(20,25,10));

delete(h2); 

set(a(2),'ycolor', get(a(1), 'ycolor'));