MATLAB Programming Fundamentals - MathWorks

Support Variable Number of Inputs

This example shows how to define a function that accepts a variable number of input

arguments using varargin. The varargin argument is a cell array that contains the

function inputs, where each input is in its own cell.

Create a function in a file named plotWithTitle.m that accepts a variable number of

paired (x,y) inputs for the plot function and an optional title. If the function receives an

odd number of inputs, it assumes that the last input is a title.

function plotWithTitle(varargin)

if rem(nargin,2) ~= 0

myTitle = varargin{nargin};

numPlotInputs = nargin - 1;

else

myTitle = 'Default Title';

numPlotInputs = nargin;

end

plot(varargin{1:numPlotInputs})

title(myTitle)

Because varargin is a cell array, you access the contents of each cell using curly braces,

{}. The syntax varargin{1:numPlotInputs} creates a comma-separated list of inputs

to the plot function.

Call plotWithTitle with two sets of (x,y) inputs and a title.

x = [1:.1:10];

y1 = sin(x);

y2 = cos(x);

plotWithTitle(x,y1,x,y2,'Sine and Cosine')

You can use varargin alone in an input argument list, or at the end of the list of inputs,

such as

function myfunction(a,b,varargin)

21 Function Arguments