It is an unordered collection (meaning you won't get the elements in the same order as you defined) of unique, non-nil elements. It must conform to the Hashable protocol . This means it has to provide a hashValue property. This is important because sets are unordered and hashValue is used to access the elements of the sets.
Access time is more efficient than arrays. When searching for an element inside an array, the worst scenario is O(n), where n is the size of the array, but in a set, it is always constant O(1). Unlike other collection types while declaring sets, a set type must be ...
