Learn Kotlin Yesterday

A guide to learning Kotlin (fast!) for developers who can already code in other languages.

Overview

This repo contains a document and code examples that cover the core principles & techniques of using the Kotlin programming language. I developed it as I needed to get up to speed with Kotlin as quickly as possible - and figured that my write-up and demo projects might be useful to any other devs who may need to learn Kotlin quickly, too.

Topics Covered / Chapters:

00 - Intro / Overview / Use Case
01 – Kotlin Basics and Compiling from the Command Line
02 - Classes, Types, and Basic Syntax
03 - Organising Code, Imports, and Packages
04 - Extending Classes & Implementing Interfaces
05 - Singletons, Functions, Parameters, and Arguments
06 – Further Classes and Functions, Companion Objects, and Java/Kotlin Interaction
07 – Smart Casts and Type Checking
08 – Flow Control
09 – String Templates and Multi-Line Strings
10 – References, Values, Types, and Equality
11 – Collections and Streams
12 – Loops and Iteration
13 – VarArg Parameters
14 – Filtering Data in Collections
15 – Running Map, Reduce, and Sort on Collections
16 – Working with Ranges and Progressions
17 – Extension Functions
18 – Extension Properties
19 – Higher Order Functions and Lambda with Receiver
20 – Overloading Operators
21 – Working with Generics
22 – Infix Function Calls

Erata / Feedback

Any and all feedback is cordially invited =D Please feel free to raise an issue if you feel something isn't quite right, or make some changes and submit a pull request if you'd prefer. If taking the PR route and modifying the Word document (whether in Word or LibreOffice or similar), please be aware that Track Changes is enabled in the document, so please leave it on when making any adjustments so I can see what's changed & where (although you don't have to update the PDF or HTML document versions - I'm happy to take care of that).

To protect your anonymity, prior to including any changed version of the document in a PR you may wish to create a version with all metadata removed by (in Windows) right-clicking on the document, then selecting Properties from the pop-up menu, then in the Details tab click Remove Properties and Personal Information then make sure Create a copy with all possible properties remove is selected and click [OK]:

TODO:

Add/edit text in chapters that are missing write-up (all the code is there - just not some of the discussion around it).
Add Windows versions of IntelliJ IDEA projects (I don't think Linux projects open cleanly in Windows? Or is it that Windows projects don't open cleanly in Linux? Anyways, check & try to get a single set of projects across Linux/Windows - and failing that create Windows versions of the projects).
Fix issue with bad/missing characters in HTML version of document as rendered via github pages.

alansley / learnkotlinyesterday Goto Github PK