Swift - Identity Operators

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Identity operators are used to check whether the given constants or variables refer to the same instance or not. These operators are generally used with objects or classes because they are reference types. These operators are different from equality operators.

Equality operators check if the two given values are equal to not whereas the identity operators check if the two given variables refer to the same reference or not. Swift supports two types of identity operators −

Identical to Operator in Swift

Identical to "===" operator is used to check whether the given two constants or variables refer to the same instance of the class or not. If yes, then this operator will return true.

Otherwise, this operator will return false. This operator compares the reference not the content of the objects.

Syntax

Following is the syntax of the Identical to operator −

myVariable1 === myVariable2

Example

Swift program to check if the given variables refer to the same object or not.

import Foundation

// Class
class TutorialsPoint {
   var empName: String
    
   init(empName: String) {
      self.empName = empName
   }
}

// Creating object of TutorialsPoint class
let object1 = TutorialsPoint(empName: "Monika")
let object2 = object1 

// Checking if both variables refer to the same object or not
// Using identical to (===) operator
if object1 === object2 {
   print("YES! Both object1 and object2 are identical")
} else {
   print("NO! Both object1 and object2 are not identical")
}

Output

YES! Both object1 and object2 are identical

Not Identical to Operator in Swift

The Not Identical to "!==" operator is used to check whether the given variables do not refer to the same operator or not. If yes, then this operator will return true. Otherwise, it will return false.

Syntax

Following is the syntax of Not Identical to Operator −

myVariable1 !== myVariable2

Example

Swift program to check if two variables do not refer to the same object or not using not identical to "!==" operator.

import Foundation

// Class
class Author1 {

   var bookName: String
    
   init(bookName: String) {
      self.bookName = bookName
   }
}
class Author2 {
   var bookName: String    
   init(bookName: String) {
      self.bookName = bookName
   }
}

// Creating objects
let obj1 = Author1(bookName: "Tales of Mumbai")
let obj2 = Author2(bookName: "Right to find")

// Using not identical to (!==) operator
if obj1 !== obj2 {
   print("They are identically not equal")
} else {
   print("They are identically equal")
}

Output

They are identically not equal