Search icon CANCEL
Arrow left icon
Explore Products
Best Sellers
New Releases
Books
Videos
Audiobooks
Learning Hub
Conferences
Free Learning
Arrow right icon
Arrow up icon
GO TO TOP
Kotlin Quick Start Guide

You're reading from   Kotlin Quick Start Guide Core features to get you ready for developing applications

Arrow left icon
Product type Paperback
Published in Aug 2018
Publisher Packt
ISBN-13 9781789344189
Length 178 pages
Edition 1st Edition
Languages
Tools
Arrow right icon
Author (1):
Arrow left icon
Marko Devcic Marko Devcic
Author Profile Icon Marko Devcic
Marko Devcic
Arrow right icon
View More author details
Toc

Type inference


Declaring types in Kotlin is optional. This is a feature of a Kotlin compiler called Type inference. The compiler can infer the type from the context of the usage. Kotlin is a strongly and statically typed language, so omitting types doesn’t mean that you lose type safety. 

Here’s an example of type inference:

val str = "Kotlin"

str variable is of type String and the compiler knows this from the String literal that is initializing the variable. That’s why, if you try to assign a different type to this variable, you'll get a compiler error, as can be seen in the following:

var str = "Kotlin"
str = 1 // compiler error

Type inference doesn’t just work on local variables, but also on functions with expression bodies, generic types, closures and lambdas. You’ll see more type inference in practice in following chapters.

lock icon The rest of the chapter is locked
Register for a free Packt account to unlock a world of extra content!
A free Packt account unlocks extra newsletters, articles, discounted offers, and much more. Start advancing your knowledge today.
Unlock this book and the full library FREE for 7 days
Get unlimited access to 7000+ expert-authored eBooks and videos courses covering every tech area you can think of
Renews at $19.99/month. Cancel anytime