update instance property data without creating a new object?

How can I update a property without creating a new instance, using an instance method? For example:

   classdef TestClass
      properties
          A = [];
      end
      methods
          function obj=updateA(obj, val)
              obj.A = val;
          end
      end
  end

This will update A:

x = TestClass
x.A = 5;

However,

x.updateA(10)

will not update the instance x, but will create a new instance with the modified A. How can I update the property A of x using a class method without creating a new instance?

Answer 1

[Adam]

x = x.updateA(10)

will update the current object.

Or you can derive your class from 'handle' to make it a pass-by-reference class which does not need to re-assign obj, but beware this has other implications too.

[Shay Ohayon]

x = x.updateA(10) will work, but it's kinda ugly. I'll look into the handle option. Thanks!

[Adam]

Well, that's the way pass-by-value classes work, you always have to reassign to the object. It was not at all intuitive to me either when I first did it (and still now since I use mostly handle-derived classes) since I came from a C++ background rather than some other language where this concept is also explicit.