MATLAB Programming Fundamentals - MathWorks

Deleting Handle Objects

To remove an object referenced by any number of handles, use delete. Given hobj1 and

hobj2, which both refer to the same object, delete either handle. MATLAB deletes the

object:

hobj1 = HdClass(8);

hobj2 = hobj1;

delete(hobj1)

hobj2

hobj2 =

handle to deleted HdClass

Use clear to remove the variable from the workspace.

Modifying Objects

When you pass an object to a function, MATLAB passes a copy of the object into the

function workspace. If the function modifies the object, MATLAB modifies only the copy of

the object that is in the function workspace. The differences in copy behavior between

handle and value classes are important in such cases:

• Value object — The function must return the modified copy of the object. To modify the
  object in the caller’s workspace, assign the function output to a variable of the same
  name


• Handle object — The copy in the function workspace refers to the same object.
  Therefore, the function does not have to return the modified copy.

Testing for Handle or Value Class

To determine if an object is a handle object, use the isa function. If obj is an object of

some class, this statement determines if obj is a handle:

isa(obj,'handle')

For example, the containers.Map class creates a handle object:

hobj = containers.Map({'Red Sox','Yankees'},{'Boston','New York'});

isa(hobj,'handle')

16 Using Objects