Equality (== structural vs === referential) in Kotlin - Hands-On Comparison

Equality (== structural vs === referential)

📖 Scenario: Imagine you have two boxes that look the same. You want to check if the boxes have the same things inside or if they are actually the same box.

🎯 Goal: You will learn how to check if two variables in Kotlin have the same content (structural equality) or if they point to the exact same object (referential equality).

📋 What You'll Learn

Create two variables holding strings with the same text

Create a variable holding a different string

Create a variable to store the result of structural equality check

Create a variable to store the result of referential equality check

Print the results of both equality checks

💡 Why This Matters

🌍 Real World

Understanding equality helps when you want to compare data in apps, like checking if two user inputs are the same or if two objects represent the same thing.

💼 Career

Many programming jobs require knowing how to compare data correctly to avoid bugs, especially when working with objects and data structures.

1

Create two string variables with the same text

Create two variables called text1 and text2 and set both to the string "hello".

Kotlin

# Your code here

Need a hint?

Use val to create variables and assign the string "hello" to both.

2

Create a different string variable

Create a variable called text3 and set it to the string "world".

Kotlin

val text1 = "hello"
val text2 = "hello"
# Your code here

Need a hint?

Create text3 with the value "world".

3

Check structural and referential equality

Create a variable called structuralEqual that stores the result of text1 == text2 and a variable called referentialEqual that stores the result of text1 === text2.

Kotlin

val text1 = "hello"
val text2 = "hello"
val text3 = "world"
# Your code here

Need a hint?

Use == for structural equality and === for referential equality.

4

Print the results of equality checks

Print the values of structuralEqual and referentialEqual using two separate println statements.

Kotlin

val text1 = "hello"
val text2 = "hello"
val text3 = "world"
val structuralEqual = text1 == text2
val referentialEqual = text1 === text2
# Your code here

Need a hint?

Use println(structuralEqual) and println(referentialEqual) to show the results.