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

Functional collections

Functional collections are collections that offer a way to interact with its elements through high-order functions. Functional collections have common operations with names such as filter, map, and fold; these names are defined by convention (similar to a design pattern) and are being implemented in several libraries and languages.

Don't get confused with purely functional data structures—a data structure implemented in a pure functional language. A purely functional data structure is immutable and uses the lazy evaluation and other functional techniques.

Functional collections can but needn't necessarily be purely functional data structures. We have already covered how imperative implementations of algorithms can be faster than functional ones. 

Kotlin comes with an excellent functional collection library. Let's have a look at it:

val numbers: List<Int> = listOf(1, 2, 3, 4)

Our value numbers as a List<Int> type. Now, let's print its members as follows:

fun main...