What is NSCountedSet?

NSCountedSet keeps track of the number of times objects are inserted and requires that objects be removed the same number of times. The count method defined by the superclass NSSet has special significance; it returns the number of distinct objects, not the total number of times objects are represented in the set.

What is an NSSet?

An object representing a static, unordered collection of unique objects.

What is NSDictionary?

The NSDictionary class declares the programmatic interface to objects that manage immutable associations of keys and values. Each entry consists of one object that represents the key and a second object that is that key’s value. Within a dictionary, the keys are unique.

Is Swift set ordered?

Swift provides three primary collection types, known as arrays, sets, and dictionaries, for storing collections of values. Arrays are ordered collections of values. Sets are unordered collections of unique values.

What is a difference between NSArray and NSSet?

The main difference is that NSArray is for an ordered collection and NSSet is for an unordered collection. If you’re iterating through an unordered collection, NSSet is great.

What is NSString?

An NSString object encodes a Unicode-compliant text string, represented as a sequence of UTF–16 code units. The objects you create using NSString and NSMutableString are referred to as string objects (or, when no confusion will result, merely as strings). The term C string refers to the standard char * type.

What is difference between NSArray and NSMutableArray?

The primary difference between NSArray and NSMutableArray is that a mutable array can be changed/modified after it has been allocated and initialized, whereas an immutable array, NSArray , cannot. When using this method of constructing your arrays, pass your objects that need to be placed inside the array one by one.

What is an NSArray in Swift?

An object representing a static ordered collection, for use instead of an Array constant in cases that require reference semantics.

How do you define a set in Swift?

A set is an unordered collection of unique elements. A set in Swift is declared using one form: Set . Set() creates an empty set of strings. Swift is able to infer the set type, so the type annotation : Set is optional.