Swiftly

Swift 5.1 references for busy coders

Identity operators (===, !==)

Identity operators return a Bool to indicate whether or not two variables are pointing to (referencing) the exact same class instance in memory. They are used heavily in if statements.

They cannot be used on struct instances, because structs are value types, not reference types.

Comparing two class instances

class Player {
  var name: String
  var score: Int

  init(name: String, score: Int) {
    self.name = name
    self.score = score
  }
}

let player1 = Player(name: "Tomoko", score: 100)
let player2 = Player(name: "Tomoko", score: 100)
let player3 = Player(name: "Isabella", score: 350)
let player4 = player1

print(player1 === player2) // false
print(player1 === player3) // false
print(player1 === player4) // true

print(player1 !== player2) // true
print(player1 !== player3) // true
print(player1 !== player4) // false