matlab function with argument not required

Question

I create a function

function y = getValue(modelName, param, option)
    open_system(modelName);
    runModel(option);
    y = getActiveFun(param);
end

I would like when calling this function to have the choice to pass or not argument option from some other files I call the function with all arguments and sometimes I would like to call it without passing option argument ?

I would like to call : getValue(modelName, param) from other files

How could I do that ?

Answer 1

The simplest way to do this is to use the nargin variable:

function y = getValue(modelName,param,option)
    open_system(modelName);

    if (nargin < 3)
        # No option passed, do something like
        runModel('defaultOption')
    else
        # Option passed
        runModel(option);
    end
    y = getActiveFun(param);
end

nargin is just the number of input arguments that were actually submitted. Thus, nargin == 3 indicates that the option parameter has been set, nargin < 3 that it has not been set.

Thus, you could now always call your function like

result = getValue('myModel', myParameter)

or with all parameters

result = getValue('myModel', myParameter, someOption)