nargin - Number of function input arguments

Examples

Inputs to Current Function

Create a function in a file named addme.m that accepts up to two inputs, and identify the number of inputs with nargin.

function c = addme(a,b)

switch nargin
    case 2
        c = a + b;
    case 1
        c = a + a;
    otherwise
        c = 0;
end

Inputs Defined for a Function

Determine how many inputs a function can accept.

The function addme created in the previous example has two inputs in its declaration statement (a and b).

fx = 'addme';
nargin(fx)

ans =
     2

Function with varargin Input

Determine how many inputs a function that uses varargin can accept.

Define a function in a file named mynewplot.m that accepts numeric inputs x and y and any number of additional plot inputs using varargin.

function mynewplot(x,y,varargin)
   figure
   plot(x,y,varargin{:})
   title('My New Plot')

At the command line, query how many inputs newplot can accept.

fx = 'mynewplot';
nargin(fx)

ans =
    -3

The minus sign indicates that the third input is varargin. The mynewplot function can accept an indeterminate number of additional input arguments.