Determines whether a given object is present in the set, and returns that object if it is.
- iOS 2.0+
- macOS 10.0+
- tvOS 9.0+
- watchOS 2.0+
An object to look for in the set.
Returns an object equal to
object if it's present in the set, otherwise
Each element of the set is checked for equality with
object until a match is found or the end of the set is reached. Objects are considered equal if