Audrey's Kotlin for Developers Cheatsheet

kotlin_for_devs_cheatsheet.md

Variables

Declare var for a mutable variable:

var name = "Mommy"
name = "Uma"

Declare val for a read-only constant:

val pi = 3.14

Increment and decrement operators:

var toyCount = 4
toyCount++
toyCount--

Double for decimal values:

var starValue: Double = 0.1

Functions

fun greeting(): String {
    return "Hello!"
}

println(greeting())

Classes

class Person(var name: String)

val person = Person("John")
person.name = "Jane"

Collections

val numbers = mutableListOf(1,2,3)
numbers.add(4)

val numsSet = setOf(1,2,3)
println(numsSet.contains(2))

Control Flow

fun max(a: Int, b: Int): Int {
    return if (a > b) a else b
}

val result = max(1, 2)