indexOfObject vs. indexOfObjectIdenticalTo

Question

What is the difference between these two NSArray methods?

Answer 1

indexOfObjectIdenticalTo checks for the exact same id (same address). indexOfObject checks that isEqual: returns YES.

Answer 2

The first uses isEqual: to find a matching object, while the second looks for the same object (i.e., the object at the same memory location).

Answer 3

indexOfObjectIdenticalTo is far more faster than indexOfObject but it uses pointer comparison == instead of calling isEqual:

If you are searching for a pointer match, always use indexOfObjectIdenticalTo to get peak performance