Book Image

Functional Kotlin

Book Image

Functional Kotlin

Overview of this book

Functional programming makes your application faster, improves performance, and increases your productivity. Kotlin supports many of the popular and advanced functional features of functional languages. This book will cover the A-Z of functional programming in Kotlin. This book bridges the language gap for Kotlin developers by showing you how to create and consume functional constructs in Kotlin. We also bridge the domain gap by showing how functional constructs can be applied in business scenarios. We’ll take you through lambdas, pattern matching, immutability, and help you develop a deep understanding of the concepts and practices of functional programming. If you want learn to address problems using Recursion, Koltin has support for it as well. You’ll also learn how to use the funKtionale library to perform currying and lazy programming and more. Finally, you’ll learn functional design patterns and techniques that will make you a better programmer.By the end of the book, you will be more confident in your functional programming skills and will be able to apply them while programming in Kotlin.
Table of Contents (22 chapters)
Title Page
Copyright and Credits
Packt Upsell

Set and MutableSet

Just like List, Set also has the following two variants in Kotlin:

  • Set
  • MutableSet

Set is read-only and MutableSet is the mutable version of Set, which contains the read-write functionalities.


Just like with list, set values also have read-only functions and properties like size, iterator(), and so on. We are skipping mentioning them here to avoid redundant contents in this book. Also, please note that set doesn't do ordering like list (unless you use OrderedSet). So, it lacks the functions which involve orders like indexOf(item), add(index, item), and so on.

Sets in collections represent mathematical sets (as in set theory).

The following is an example with MutableSet:

fun main(args: Array<String>) { 
    val set = mutableSetOf(1,2,3,3,2) 
    println("set $set") 
    println("set $set") 

The following is the output:

The output clearly shows that, even though we added multiple duplicate items to...