argument in function from class

I have a question about the function in the class. I have main.m and my_class.m . my_class has following function,

classdef my_class
  ... 
  function 
       [x,y,z,w] = get_File(pathname,filename)
       completename = fullfile(pathname,filename);
       data = load(completename);
       x = data(:,1);
       y = data(:,2);
       .....
  end
end

here simply trying to load the file from pathname and filename as input. But when main.m tries to include this function by

pathname = 'my pathname';
filename = 'my filename';
obj = my_class;
[a,b,c,d] = obj.get_File(pathname,filename);

error shows up as follows

Error using my_class/get_File
Too many input arguments.

Error in Untitled (line 4)
[a,b,c,d] = obj.get_File(pathname,filename);

Seems this error will disappear if I set the function as

function 
     [x,y,z,w] = get_File(~,~) %<--- here its changed
     pathname = 'my pathname';
     filename = 'my filename';
     completename = fullfile(pathname,filename);
     data = load(completename);
     x = data(:,1);
     y = data(:,2);
     .....
end

and include in main.m like

obj = Tomography_Tool;
[a,b,c,d] = obj.get_File;

can anybody explain why I got the error and disappear by this modification?

thank you for your help,

Answer 1

[Steven Lord]

When you call the method like:

 [a,b,c,d] = obj.get_File(pathname,filename);

you're calling it with THREE input arguments, not two. As stated in the documentation, these two commands are equivalent in most circumstances.

 [a,b,c,d] = obj.get_File(pathname,filename);
 [a,b,c,d] = get_File(obj,pathname,filename);

They even have the same number of characters, though the first has a period and the second a comma.

So either define your function differently:

function [x,y,z,w] = get_File(obj,pathname,filename)

or, if get_File doesn't actually use the object (the section you quoted doesn't, though perhaps part of the code you snipped out does) make it a static method or perhaps a plain old function.

[k38]

Hi Steven, thank you very much for your help!! It saved my day:)