Part of the Play Framework with Scala in Action session of the Nov 2013 Desert Code Camp. Scala Basics with the REPL. To use these, please install Scala 2.10.x and then use either type in or use the :paste mode of the REPL to copy/pase the following examples.

repl_example1.scala

val foo = "foo"
foo = "Bar"

var bar = "Bar"

foo + bar

repl_example2.scala

val names = List[String]("Foo", "Bar", "Blaz")
names(1)

names.foreach { name => s"Hi, I'm $name!" }

names.mkString(",")

names.map {
  name =>
    name.getBytes
}

repl_example3.scala

//  basic pattern matching
def basic(s : String) = s match {
  case "a" => "match!"
  case _ => "don't care - try again"
}

def weatherByZip(maybeZip : Option[Int]) =  maybeZip match {
    case Some(zip) => s"Weather for $zip should be sunny and pleasant!"
    case None => s"No zip!"
}

val northPeoriaZip = Some(85383)
val newTownZip = None

weatherByZip(northPeoriaZip)
weatherByZip(newTownZip)

northPeoriaZip.getOrElse("Not provided!")
newTownZip.getOrElse("Not Provided")

def getTemp(zip : Int) = zip match {
  case 85383 => Some(72)
  case _ => None
}

northPeoriaZip.map { maybeZip => getTemp(maybeZip) }

northPeoriaZip.flatMap(getTemp(_)).getOrElse(-272)

repl_example4.scala

import java.net.URL
import scala.util.{ Try, Success, Failure }

def path(urlString :String) = {
  Try(new URL(urlString))
}

path("asdf").getOrElse("Invalid URL!")

path("http://www.desertcodecamp.com/schedule").getOrElse("Invalid URL!")

repl_example_5.scala

case class Foo(sum : Int, name : String, time : Option[Long] = None)

var myFoo = Foo(1, "Terry")

myFoo.sum

myFoo.time.getOrElse("0")

//myFoo.sum += 1

val updatedFoo = myFoo.copy(sum = 3, time = Some(1000L))

myFoo.sum

updatedFoo.sum

def printSum(foo: Any) = foo match {
  case Foo(1, _, _) => println("I'm #1")
  case Foo(sum, _, _) => println(s"sum -> $sum")
  case _ => println("not a Foo - wtf?")
}

printSum(myFoo)
printSum(updatedFoo)
printSum(null)