MATLAB: How to copy an object that is not a graphic one

MATLABoop

Hi,

I have an object of a class which I defined. I would like to make a copy of that object. But copy or copyobj do not seem to work. What should I do?

Thanks!

Best Answer

In general, you would have to write a copy() method specific to the needs of your class. The copy() method would have to call the class constructor with suitable arguments to generate a copy.

If your class is sufficiently simple that a copy can be made just by dot-indexing all of the non-Dependent, public property values and writing them to a second object,

   objcopy.prop1 = obj.prop1;
   objcopy.prop2 = obj.prop2;
   etc...

then you can just use my attached copyprops() utility, which automates this.

Related Solutions

MATLAB: How to keep the SetMethod and GetMethod of the dynamic properties when saving and loading the class instance in MATLAB R2019a

You need to implement your own saveobj and loadobj. In the saveobj you convert your class instance into a struct and store some meta information about your dynamic properties. In the loadobj you convert the previously created struct back into your class instance. See the example below:

classdef myCls < dynamicprops
    properties
        Prop1
        Prop2
    end
    methods
        function s = saveobj(obj)
            s.Prop1 = obj.Prop1;
            s.Prop2 = obj.Prop2;
            dynPropNames = setdiff(properties(obj), {'Prop1' 'Prop2'});
            for i=numel(dynPropNames):-1:1
                p = findprop(obj, char(dynPropNames(i)));
                s.DynPropInfo(i).Name = p.Name;
                s.DynPropInfo(i).Value = obj.(p.Name);
                s.DynPropInfo(i).GetMethod = p.GetMethod;
                s.DynPropInfo(i).SetMethod = p.SetMethod;
            end
        end
    end
    methods(Static)
        function obj = loadobj(s)
            if isstruct(s)
                newObj = myCls;
                newObj.Prop1 = s.Prop1;
                newObj.Prop2 = s.Prop2;
                if isfield(s, 'DynPropInfo')
                    for i=1:numel(s.DynPropInfo)
                        p=addprop(newObj, s.DynPropInfo(i).Name);
                        p.SetMethod = s.DynPropInfo(i).SetMethod;
                        p.GetMethod = s.DynPropInfo(i).GetMethod;
                        newObj.(s.DynPropInfo(i).Name) = s.DynPropInfo(i).Value;
                    end
                end
                obj = newObj;
            else
                obj = s;
            end
        end
    end
end

MATLAB: How to declare class member data public

This behavior is supported by implementing the SUBSREF and SUBSASGN members for an object. These are invoked to handle the following cases:

A=MyClass(initial)
out = A(I)% Invoke out=A.SUBSREF(A,S)
out = A{I}
out = A.field
A(I) = in% Invoke A.SUBSASN(A,S,in)
A{I} = in
A.field = in

where S is a structure that describes the type of indexing.

More information about the SUBSASGN and SUBSREF commands can be found here:

https://www.mathworks.com/help/matlab/ref/subsasgn.html

https://www.mathworks.com/help/matlab/ref/subsref.html

Best Answer

Related Solutions

MATLAB: How to keep the SetMethod and GetMethod of the dynamic properties when saving and loading the class instance in MATLAB R2019a

MATLAB: How to declare class member data public

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