Scala Repl
Scala, screen cast, Scala REPL, Dick Wall, Escalade Software
Scala Experience
Scala class examples
Notes on Scala’s class :
Parameters of Scala methods are values (val) not variables (var)
Scala method returns the last value computed by the method
// Scala class with a private member
class Shape{
private var vertexes = 0
}
// Scala class with a method
class Shape{
def draw() : Unit = {
// Body of the method
}
}
// Scala class with a method with …
Scala Map Examples
Notes on maps :
– there is mutable and immutable maps
Examples :
import scala.collection.mutable.Map
val rucksack = Map[Int, String]()
rucksack += (1 -> “shawl”)
rucksack += (2 ->”gloves”)
rucksack += (3->”hat”)
println(rucksack)
val ruckSackPile = Map[Int, String](1 -> “shawl”, 2 ->”gloves”, 3->”hat”)
println(ruckSackPile)
Reference:
1. Programming in Scala: A Comprehensiv e Step-by-step Guide
Scala Sets Examples
Notes on sets :
– Scala provides mutable and immutable sets. (scala.collection.mutable, scala.collection.immutable )
Sets examples :
– Sets creating, initializating
scala> import scala.collection.mutable.Set
scala> val teniscordVisitorsSet = Set(“Players”, “Watchers”)
scala> tenisCordVisitorsSet += “Referees”
scala>import scala.collection.immutable.HashSet
scala>val tenisCordVisitorsSet = HashSet(“Players”, “Watchers”)
Reference :
1. Programming in Scala: A Comprehensiv e Step-by-step Guide
Scala Tuples Examples
My notes on tuples :
– tuples are immutable, but unlike lists, tuples can contain different types of elements
– tuples are very useful when you need to return multiple objects
Tuples examples :
– Access to element of tuple
scala > val pair = (99, “Luftballons”)
scala > println(pair._1)
scala > println(pair._2)
Reference :
1. Programming in Scala: A Comprehensiv e Step-by-step Guide
Scala List Examples
My notes on scala.lists :
– scala.list is different from java.util.List
– scala.list is ‘immutable sequence of objects’
– scala list doesn’t support append operation
Some Scala list operators and methods:
::: – for list concatenation
scala > val oneTwo = List(1, 2)
scala > val threeFour = List(3, 4)
scala > val oneTwoThreeFour = oneTwo ::: threeFour
:: – cons operator – prepends …
Arrays in Scala and its tricky behaviour ;-)
The row bellow shows parametrizing of an array with a String type in Scala.
scala > val greetStrings = new Array[String](3)
If I have to be honest it’s very unclear what is the meaning of “parametrizing of an array” and why is not used the word “definition” ;-). Every time when I read for Scala I see …
A little Scala Quiz ;-)
Scala examples
Scala Variables
Definition of variable with var and val in Scala and the elegant way of definition.
Hello World in Scala II ;-)
Notion about Scala’s object.