function with variable amount of inputs

Hello everybody,

maybe this is very simple question for you guys, but I'm trying to write a function in matlab that works when having just 2 inputs or more. I have been looking for a solution, but couldn't find exactly what I wanted. It is like this

function myfunction(x1,y1,x2,y2)

plot(x1,y1) %user just puts x1,y1

or

plot(x1,y1,x2,y2) %user puts x1,y1,x2,y2

end

I want the function to work, when the user just puts x1,y1 as input, but I also want it to work when the user puts x1,y1,x2,y2 and plot a figure.

Many thanks in advance.

Romano

Answer 1

[Stephen23]

Use nargin:

function myfun(x1,y1,x2,y2)
switch nargin
    case 2
        plot(x1,y1)
    case 4
        plot(x1,y1,x2,y2)
    otherwise
        error('This number of arguments is not supported')
end
end

Or for the general case you can use varargin: this has the disadvantage that the inputs are not named, so tab completion and the code helper tools will only show varargin instead of more useful variable names.

Answer 2

[Walter Roberson]

See the documentation for varargin and nargin