Kotlin tutorials

Reviews on best tutorials for those, who want to master Kotlin
02 June 2017   3077

Kotlin is one of the youngest programming languages. Despite it, Kotlin is now available for Android apps coding. The authors set a goal to create a more concise and type-safe language than Java, and simpler than Scala.

Kotlin

Statically-typed programming language that runs on the Java Virtual Machine and also can be compiled to JavaScript source code

This two facts made Kotlin super popular for studing. In this review, we will provide you with a list of the best Kotlin's tutorials.

Try Kotlin

Try Kotlin interfaceTry Kotlin interface

Interactive official Kotlin tutorial. In-browser coding, tons of examples and step-by-step learning. Will fit for newbies and skilled coders who want to master Kotlin. Also, some interesting information available at official Kotlin webpage here.

Kotlin Link

Kotlin Link interfaceKotlin Link interface

Giant database for every Kotlin fan. Contains links for books, courses, tests, official webpages, tools and many other. Simple desing and handy navigation.

KotlinLang.Ru

KotlinLang.Ru interface
KotlinLang.Ru interface

Online database for russian Kotlin coders. Contains a lot of translated materials. Website is opensourced, everybody can help to develop it by translating and editing the materials. 

Books

Kotlin in Action

Kotlin in Action
Kotlin in Action

Book for skilled Java coders, written by Dmitry Jemerov and Svetlana Isakova, developers in the Kotlin team. Rich for examples, this book covers interesting topics like creating DSLs with natural language syntax. Free preview available here

Modern Web Development with Kotlin

Modern Web Development with Kotlin
Modern Web Development with Kotlin

As you can see from the heading, this book is about web development using Kotlin. It covers basics to get started with concentration on the practical aspect of using the language. It guides you through the creation of a technology-packed Web application using popular backend and frontend technologies. Available here.

Which tutorial was the most interesting for you?

Kotlin is the programming language by JetBrains, a well-known developers from Saint-Petersburg, Russia. It is the 2nd official supported language for Android application development. We've collected the best tutorials for this language. Please, share your thoughts about the best Kotlin tutorial in your opinion.

How to convert list to map in Kotlin

Two ways to convert list to map in Kotlin, with code examples
31 October 2017   535

For example, you have a list of strings like:

val list = listOf("a", "b", "c", "d")

and you need to convert it to a map, where the strings are the keys.

There are two ways to do this:

The first and most performant is to use associateBy function that takes two lambdas for generating the key and value, and inlines the creation of the map:

val map = friends.associateBy({it.facebookId}, {it.points})

The second, less performant, is to use the standard map function to create a list of Pair which can be used by toMap to generate the final map:

val map = friends.map { it.facebookId to it.points }.toMap()