MATLAB: Can I detect array index inside setter method

class objectoopsetterstatic data object

Is there a way to detect the index/position of the setted value inside a new defined setter method?
I mean, if I call
obj.Prop(idx) = val;
that 
function set.Prop(obj,val)
    if % idx > 5
            
        val = ...;
        
    end
    obj.Prop = val;
end
does different calculations on specific indices.
THX
In MATLAB documentation is a short description I don't really understand________________________________________
Access Methods and Properties Containing Arrays
You can use array indexing with properties that contain arrays without interfering with property set and get methods.
For indexed reference:
val = obj.PropName(n);
MATLAB calls the get method to get the referenced value.
For indexed assignment:
obj.PropName(n) = val;
MATLAB:
  • Invokes the get method to get the property value
  • Performs the indexed assignment on the returned property
  • Passes the new property value to the set method

Best Answer

"For indexed assignment:
obj.PropName(n) = val;
MATLAB:
  • Invokes the get method to get the property value
  • Performs the indexed assignment on the returned property
  • Passes the new property value to the set method"
If I am understanding this correctly, then
obj.PropName(n) = val;
is essentially similar to
myProp = obj.PropName; % get method
myProp(n) = val;
obj.PropName = myProp; % set method
so that neither the get method nor the set method ever sees n.
You could compare obj.Prop to val within your set method before you set obj.Prop so that you can determine which value is being changed, but that doesn't seem like a very good solution. You could also look into overloading subsasgn for your object, which might do the trick (requiring that you explicitly call subsasgn within your class rather than use '()' and '.', see here for explanation). Though I hope I'm overlooking a simpler solution.
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