Loading data in a function and passing it

Hello all. I'm trying to write a function that checks for the existence of a series of variables. If they exist, I want the function to do nothing. If they don't exist, I want the function to load them into the workspace and pass them to the main workspace. When I run my code however, it loads the first file and assigns it to variable ans. Any help is appreciated.

function [cntREF, sREFn, w] = LoadClassData
%%%%Loads the preset data created by the training algorithm

   if exist('B', 'var') == 1
       return;
   else
      load('B.mat');
   end

if exist('cntREF', 'var') == 1
    return;
else
     load('cntREF.mat');
end

if exist('sREFn', 'var') == 1
    return;
else
    load('sREFn.mat');
end

if exist('w', 'var') == 1
    return;
else
    load('w.mat');
end

end

[Richard Prince]

Also I should mention above that when I run the function with the variables already in place it is executing the else statements anyway. Is this some kind of local workspace problem?

Answer 1

[Jan]

Each function has its own WorkSpace. Because your function does not have any input, there are no variables defined at the beginning:

function [cntREF, sREFn, w] = LoadClassData
if exist('B', 'var') == 1
   % Cannot happen under any circumstances
end

Now you can load the MAT file to the variable B, but it is not provided as output and therefore it does not appear in the caller. The is the meaning of functions: hide everything, what happens internally except for inputs and outputs.

[Richard Prince]

Thanks that clears it up quite a bit. Is there a way to effectively implement what I want in a function, or should I just move all the if-statements into the body of the main code?

Answer 2

[kowshik Thopalli]

In the else condition- write b=load('b.mat'), w=load('w.mat') etc. Does this solve your problem?

[Richard Prince]

No this changes the datatype of the variable being loaded. Also I should mention above that when I run the function with the variables already in place it is executing the else statements anyway. Is this some kind of local workspace problem?

[kowshik Thopalli]

Yes You are right. It becomes a structure.You have to then access using b.b; Yes. Functions have their own work space which is different from base workspace . Return the loaded matfiles to the script that calls this function.