varargin

How can I check the input argument of a function to see if a specific string has been input? For example, I want to see if the user has input 'filename' in the function argument then the function reads the file name in the argument as well and writes the data into it otherwise doesn't write anything to any file.

myfunc(x, y, z, 'filename', 'mydata.txt') ---> writes to mydata.txt

myfunc(x, y, z) ---> does not write to any file

Actually, I have 10 possible cases and I want to be able to check which of those cases is in the input argument and based on that take the appropriate action like plot function which you can specify 'color', linewidth', 'linetype', and other plot properties arbitrarily.

Thanks, Ahmad

Answer 1

[Daniel Shub]

doc inputParser

With 10 possibilities, I think an inputParser object is the way to go. With only 1 or two possibilities, the inputParser might also be teh way to go.

Answer 2

[the cyclist]

Define the function with

 function [output] = myfunc(x,y,z,varargin)

then you can use nargin() to count how many inputs there were, and also see what values are stored in varargin.

[AP]

I need something more general because my input arguments are about 10 and in the example I mentioned previously, only 'filename' is shown. Those 10 inputs can be arbitrarily specified. To clarify what I mean, I need to write a function like plot which you can specify 'color', linewidth', 'linetype', and other properties arbitrarily.

[James Tursa]

Then do what the cyclist suggested with a slight variation:

function varargout = myfunc(varargin)

Then run a loop over varargin, testing each input individually, and act accordingly.

[AP]

This is what I was thinking but is there any command so that I can search in the cell array of VARARGIN? I tried ismember and strfind but they didn't work. do you have any suggestion?