MATLAB Function Reference
plotyy

Create graphs with y axes on both left and right side

Syntax

• ```plotyy(X1,Y1,X2,Y2)
plotyy(X1,Y1,X2,Y2,'function')
plotyy(X1,Y1,X2,Y2,'function1','function2')
[AX,H1,H2] = plotyy(...)
```

Description

`plotyy(X1,Y1,X2,Y2)` plots `X1` versus `Y1` with y-axis labeling on the left and plots `X2` versus `Y2` with y-axis labeling on the right.

`plotyy(X1,Y1,X2,Y2,'function')` uses the plotting function specified by the string '`function`' instead of `plot` to produce each graph. '`function`' can be `plot`, `semilogx`, `semilogy`, `loglog`, `stem` or any MATLAB function that accepts the syntax:

• ``````h = function(x,y)
``````

`plotyy(X1,Y1,X2,Y2,'function1','function2')` uses `function1(X1,Y1)` to plot the data for the left axis and `function2(X2,Y2)` to plot the data for the right axis.

`[AX,H1,H2] = plotyy(...)` returns the handles of the two axes created in `AX` and the handles of the graphics objects from each plot in `H1` and `H2`. `AX(1)` is the left axes and `AX(2)` is the right axes.

Examples

This example graphs two mathematical functions using `plot` as the plotting function. The two y-axes enable you to display both sets of data on one graph even though relative values of the data are quite different.

• ```x = 0:0.01:20;
y1 = 200*exp(-0.05*x).*sin(x);
y2 = 0.8*exp(-0.5*x).*sin(10*x);
[AX,H1,H2] = plotyy(x,y1,x,y2,'plot');
```

You can use the handles returned by `plotyy` to label the axes and set the line styles used for plotting. With the axes handles you can specify the `YLabel` properties of the left- and right-side y-axis:

• ```set(get(AX(1),'Ylabel'),'String','Left Y-axis')
set(get(AX(2),'Ylabel'),'String','Right Y-axis')
```

Use the `xlabel` and `title` commands to label the x-axis and add a title:

• ```xlabel('Zero to 20 \musec.')
title('Labeling plotyy')
```

Use the line handles to set the `LineStyle` properties of the left- and right-side plots:

• ```set(H1,'LineStyle','--')
set(H2,'LineStyle',':')

```

`plot`, `loglog`, `semilogx`, `semilogy`, axes properties: `XAxisLocation`, `YAxisLocation`