Identity comparison (===) in Swift - Mini Project: Build & Apply

Identity comparison (===) in Swift

📖 Scenario: Imagine you have two boxes that can hold toys. Sometimes, you want to check if both boxes are actually the same box, not just two boxes with the same toys.

🎯 Goal: You will create two class instances representing boxes and use identity comparison === to check if they are the exact same box.

📋 What You'll Learn

Create a class called Box with a property toy of type String

Create two variables box1 and box2 as instances of Box

Create a third variable box3 that points to the same instance as box1

Use identity comparison === to check if box1 and box2 are the same instance

Use identity comparison === to check if box1 and box3 are the same instance

Print the results of both comparisons

💡 Why This Matters

🌍 Real World

Identity comparison helps when you want to know if two variables refer to the exact same object, like checking if two references point to the same user profile in an app.

💼 Career

Understanding identity comparison is important for Swift developers working with classes, memory management, and reference types to avoid bugs and write efficient code.

1

Create the Box class and two instances

Create a class called Box with a property toy of type String. Then create two variables called box1 and box2 as instances of Box with toys "Car" and "Car" respectively.

Swift

class Box {
    var toy: String
    init(toy: String) {
        self.toy = toy
    }
}

// Create box1 and box2 instances below

Need a hint?

Define the class with a property and initializer. Then create two instances with the same toy name.

2

Create a third variable pointing to the first instance

Create a variable called box3 and assign it to the same instance as box1.

Swift

class Box {
    var toy: String
    init(toy: String) {
        self.toy = toy
    }
}

let box1 = Box(toy: "Car")
let box2 = Box(toy: "Car")

// Create box3 pointing to box1 below

Need a hint?

Assign box3 to box1 to make them point to the same box.

3

Compare box1 and box2 using identity comparison

Use identity comparison === to check if box1 and box2 are the same instance. Store the result in a variable called sameBox1and2.

Swift

class Box {
    var toy: String
    init(toy: String) {
        self.toy = toy
    }
}

let box1 = Box(toy: "Car")
let box2 = Box(toy: "Car")
let box3 = box1

// Compare box1 and box2 using === below

Need a hint?

Use === to compare if two variables point to the same instance.

4

Compare box1 and box3 and print results

Use identity comparison === to check if box1 and box3 are the same instance. Store the result in a variable called sameBox1and3. Then print both sameBox1and2 and sameBox1and3.

Swift

class Box {
    var toy: String
    init(toy: String) {
        self.toy = toy
    }
}

let box1 = Box(toy: "Car")
let box2 = Box(toy: "Car")
let box3 = box1

let sameBox1and2 = box1 === box2

// Compare box1 and box3 using === and print results below

Need a hint?

Compare box1 and box3 with === and print both results to see which boxes are the same.