plotyy

R2026b

(To be removed) Create graph with two y-axes

plotyy will be removed in a future release. Use yyaxis instead.

For information on updating your code, see Version History.

Syntax

plotyy(X1,Y1,X2,Y2)

plotyy(X1,Y1,X2,Y2,f)

plotyy(X1,Y1,X2,Y2,f1,f2)

plotyy(ax,___)

[a,p1,p2] = plotyy(___)

Description

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

plotyy(X1,Y1,X2,Y2,f) uses the specified plotting function to plot the data.

plotyy(X1,Y1,X2,Y2,f1,f2) uses the plotting function f1 to plot Y1 against X1 and the plotting function f2 to plot Y2 against X2.

plotyy(ax,___) displays the left plot in the specified axes instead of the current axes. If ax is a vector, then plotyy uses the first axes object in the vector. Specify the axes as the first argument in any of the previous syntaxes.

[a,p1,p2] = plotyy(___) returns the two axes objects in a and the two graphics objects in p1 and p2. a(1) is the left axes and a(2) is the right axes. Use a, p1, and p2 to modify the properties of the axes and plots after creating them.

Examples

Plot Two Data Sets with Different y-Axes

Plot two data sets on one graph using two y-axes.

x = 0:0.01:20;
y1 = 200*exp(-0.05*x).*sin(x);
y2 = 0.8*exp(-0.5*x).*sin(10*x);

figure
plotyy(x,y1,x,y2)

Add Title and Axis Labels

Plot two data sets using a graph with two y-axes. Add a title and axis labels.

x = 0:0.01:20;
y1 = 200*exp(-0.05*x).*sin(x);
y2 = 0.8*exp(-0.5*x).*sin(10*x);

figure
[hAx,hLine1,hLine2] = plotyy(x,y1,x,y2);

title("Multiple Decay Rates")
xlabel("Time (\musec)")

ylabel(hAx(1),"Slow Decay") % left y-axis 
ylabel(hAx(2),"Fast Decay") % right y-axis

Change Line Styles

Plot two data sets using a graph with two y-axes. Change the line styles.

x = 0:0.01:20;
y1 = 200*exp(-0.05*x).*sin(x);
y2 = 0.8*exp(-0.5*x).*sin(10*x);

[hAx,hLine1,hLine2] = plotyy(x,y1,x,y2);
hLine1.LineStyle = "--";
hLine2.LineStyle = ":";

Combine Different Types of Plots

Plot two data sets using a graph with two y-axes. Use a line plot for the data associated with the left y-axes. Use a stem plot for the data associated with the right y-axes.

x = 0:0.1:10;
y1 = 200*exp(-0.05*x).*sin(x);
y2 = 0.8*exp(-0.5*x).*sin(10*x);

figure 
plotyy(x,y1,x,y2,@plot,@stem)

Use Right y-Axis for Two Data Sets

Plot three data sets using a graph with two y-axes. Plot one set of data associated with the left y-axis. Plot two sets of data associated with the right y-axis by using two-column matrices.

x = linspace(0,10);
y1 = 200*exp(-0.05*x).*sin(x);
y2 = 0.8*exp(-0.5*x).*sin(10*x);
y3 = 0.2*exp(-0.5*x).*sin(10*x);

figure
[hAx,hLine1,hLine2] = plotyy(x,y1,[x',x'],[y2',y3']);

Input Arguments

X — x-coordinates

scalar | vector | matrix

x-coordinates, specified as a scalar, vector, or matrix.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | categorical | datetime | duration

Y — y-coordinates

scalar | vector | matrix

y-coordinates, specified as a scalar, vector, or matrix.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64 | categorical | datetime | duration

f — Plotting function

'plot' (default) | function handle | character vector

Plotting function used to plot the data, specified as a function handle or a character vector that is the name of a plotting function, for example, semilogx, semilogy, loglog, stem, or any MATLAB^® function that accepts the syntax h = function(x,y).

Example: plotyy(x1,y1,x2,y2,@loglog)

Example: plotyy(x1,y1,x2,y2,'loglog')

ax — Target axes

Axes object

Target axes, specified as an Axes object. If you do not specify the axes, MATLAB plots the first set of data into the current axes or creates an Axes object if one does not exist.

Output Arguments

a — Two axes

array of Axes objects

Two axes, returned as an array of two Axes objects. a(1) is the left axes and a(2) is the right axes. Use a to modify the properties of the axes.

p — Graphics object

graphics object

Graphics object. Use p to modify the properties of the plot after creating it.

Extended Capabilities

GPU Arrays

Accelerate code by running on a graphics processing unit (GPU) using Parallel Computing Toolbox™.

The plotyy function supports GPU array input with these usage notes and limitations:

• This function accepts GPU arrays, but does not run on a GPU.

For more information, see Run MATLAB Functions on a GPU (Parallel Computing Toolbox).

Distributed Arrays

Partition large arrays across the combined memory of your cluster using Parallel Computing Toolbox™.

The plotyy function supports distributed arrays with these usage notes and limitations:

• This function operates on distributed arrays, but executes on the client MATLAB.

For more information, see Run MATLAB Functions with Distributed Arrays (Parallel Computing Toolbox).

Version History

Introduced before R2006a

R2026b: To be removed

plotyy will be removed in a future release. Use yyaxis instead.

The yyaxis function has several advantages over the plotyy function:

• Unlike plotyy, the yyaxis function creates one Axes object with two y-axes. plotyy creates two overlaid Axes objects that can get out of sync.

• You can use yyaxis with any 2-D plotting function, including functions with varied syntaxes, such as errorbar. By contrast, plotyy is limited to working with plotting functions of the form function(x,y).

This table shows some typical uses of plotyy and how to update your code.

Not Recommended	Recommended
plotyy(x1,y1,x2,y2)	yyaxis left plot(x1,y1) yyaxis right plot(x2,y2)
plotyy(x1,y1,x2,y2,'function1','function2')	yyaxis left function1(x1,y1) yyaxis right function2(x2,y2)