Change struct property values in a class

Hi, I have a problem with using a struct as property of a value class. It seems I cannot change the values of fields (or add new fields).

The simplest example is as follows:

classdef testclass
    properties
        struct_prop=struct;
    end
    methods
        function obj = change_struct_prop(obj, val)
            obj.struct_prop.field1 = val;
        end
    end
end

Trying to change the struct_prop doesn't work:

>> a=testclass;
>> a.change_struct_prop(2);
>> a.struct_prop

ans = 

      field1: []

>>

Is there any way to manipulate a class property that is a struct (without having to define a separate class for it)? Defining the struct_prop fields in the initialisation function didn't help either.

Thanks a lot,

Olf

Answer 1

[per isakson]

Replace

    classdef testclass

by

    classdef testclass < handle

and search the help for "Comparing Handle and Value Classes"

&nbsp

In response to the comment

If a value class, replace

    >> a.change_struct_prop(2);

by

    >> a = a.change_struct_prop(2);

and read the help on the comparison of value and handle classes

[Olf]

I tried handle classes before, however I want to create an array of my class which I iteratively define by copying the (n-1)th element to the (n)th element and apply changes to that. If the class is a handle class, all instances will be identical which is not desired. Any way to get around this?

[per isakson]

See addition to answer

Answer 2

[Olf]

I found a solution that seems to have solved the issue. Instead of inheriting from the handle class I let it inherit from matlab.mixin.Copyable This gives the features from the handle class and also comes with a copy method.

classdef testclass < matlab.mixin.Copyable ...