Book Image

Hands-On Design Patterns with Kotlin

By : Alexey Soshin
Book Image

Hands-On Design Patterns with Kotlin

By: Alexey Soshin

Overview of this book

Design patterns enable you as a developer to speed up the development process by providing you with proven development paradigms. Reusing design patterns helps prevent complex issues that can cause major problems, improves your code base, promotes code reuse, and makes an architecture more robust. The mission of this book is to ease the adoption of design patterns in Kotlin and provide good practices for programmers. The book begins by showing you the practical aspects of smarter coding in Kotlin, explaining the basic Kotlin syntax and the impact of design patterns. From there, the book provides an in-depth explanation of the classical design patterns of creational, structural, and behavioral families, before heading into functional programming. It then takes you through reactive and concurrent patterns, teaching you about using streams, threads, and coroutines to write better code along the way By the end of the book, you will be able to efficiently address common problems faced while developing applications and be comfortable working on scalable and maintainable projects of any size.
Table of Contents (13 chapters)

Drop family

OK, this is cool if you have to iterate over all elements in your collection anyway. But with the for loops in Java, you could do something like this:

// Skips first two elements
for (int i = 2; i < list.size(); i++) {
// Do something here
}

How are you going to achieve that with your funky functions, huh?

Well, for that there's drop():

val numbers = (1..5).toList()
println(numbers.drop(2)) // [3, 4, 5]

Do note that this doesn't modify the original collection in any way:

println(numbers) // [1, 2, 3, 4, 5]

If you would like to stop your loop earlier, there's dropLast() for that:

println(numbers.dropLast(2)) // [1, 2, 3]

Another interesting function is dropWhile(), in which it receives a predicate instead of a number. It skips until the predicate returns true for the first time:

val readings = listOf(-7, -2, -1, -1, 0, 1, 3, 4)

println(readings.dropWhile...