Scala Cheat Sheet

object Main extends App {
  println("Hello, Scala")
}

var a = 10
val b = 20

val c: Int = 30

Int
Long
Double
Float
Boolean
Char
String

val s = "Scala"
s.length
s.toUpperCase

val name = "World"
s"Hello $name"

a + b
a - b
a * b
a / b
a % b

a == b
a != b
a > b
a < b

val r = if (a > 10) "large" else "small"

a match {
  case 1 => "one"
  case 2 => "two"
  case _ => "other"
}

for (i <- 1 to 5) {
  println(i)
}

while (a > 0) {
  a -= 1
}

def add(a: Int, b: Int): Int = {
  a + b
}

add(2, 3)

def square(x: Int): Int = x * x

def multiply(a: Int, b: Int = 2): Int = a * b

def apply(x: Int, f: Int => Int): Int = f(x)

val list = List(1, 2, 3)

list.map(_ * 2)
list.filter(_ > 1)

val v = Vector(1, 2, 3)

val set = Set(1, 2, 3)

val map = Map("a" -> 1, "b" -> 2)

for (x <- list) println(x)

list.foreach(println)

val t = (1, "a", true)

val (x, y, z) = t

class Counter {
  private var value = 0
  def increment(): Unit = value += 1
  def get: Int = value
}

class Point(val x: Int, val y: Int)

case class User(name: String, age: Int)

val u = User("A", 20)

u match {
  case User(name, age) => name
}

trait Logger {
  def log(msg: String): Unit
}

class ConsoleLogger extends Logger {
  def log(msg: String): Unit = println(msg)
}

object Config {
  val version = "1.0"
}

class Factory
object Factory {
  def create(): Factory = new Factory
}

class Box[T](val value: T)

val box = new Box(10)

val v: Option[Int] = Some(10)

v.getOrElse(0)

val r: Either[String, Int] = Right(5)

try {
  throw new RuntimeException("fail")
} catch {
  case e: Exception => e.getMessage
}

given intOrd: Ordering[Int] = Ordering.Int

def max[A](a: A, b: A)(using ord: Ordering[A]) =
  if ord.gt(a, b) then a else b

import scala.concurrent.Future
import scala.concurrent.ExecutionContext.Implicits.global

val f = Future {
  42
}

import scala.io.Source

val text = Source.fromFile("file.txt").mkString