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Kotlin Academy · Lesson

Data Class Basics: Auto-generated Methods

Understand what data class generates: equals, hashCode, toString, copy.

What Is a Data Class?

A data class is a class whose primary purpose is holding values. The Kotlin compiler auto-generates equals, hashCode, toString, copy, and componentN functions for you.

Declaring a Data Class

Prefix a regular class with data. All primary constructor parameters must be val or var.

data class User(val name: String, val age: Int)
fun main() {
    val u = User("Ada", 35)
    println(u)
}

All lessons in this course

  1. Data Class Basics: Auto-generated Methods
  2. Copying with copy() and Partial Overrides
  3. Destructuring Declarations with componentN
  4. Data Classes in Collections and as Map Keys
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