MATLAB Language Functions nargin, nargout


Example

In the body of a function nargin and nargout indicate respectively the actual number of input and output supplied in the call.

We can for example control the execution of a function based on the number of provided input.

myVector.m:

function [res] = myVector(a, b, c)
    % Roughly emulates the colon operator

    switch nargin
        case 1
            res = [0:a];
        case 2
            res = [a:b];
        case 3
            res = [a:b:c];
        otherwise
            error('Wrong number of params');
    end
end

terminal:

>> myVector(10)

ans =

    0    1    2    3    4    5    6    7    8    9   10

>> myVector(10, 20)

ans =

   10   11   12   13   14   15   16   17   18   19   20

>> myVector(10, 2, 20)

ans =

   10   12   14   16   18   20

In a similar way we can control the execution of a function based on the number of output parameters.

myIntegerDivision:

function [qt, rm] = myIntegerDivision(a, b)
    qt = floor(a / b);

    if nargout == 2
        rm = rem(a, b);
    end
end

terminal:

>> q = myIntegerDivision(10, 7)

q = 1

>> [q, r] = myIntegerDivision(10, 7)

q = 1
r = 3