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 a new element to the begging of an existing list
  scala > val twoThree = List(2,3)
  scala > valOneTwoThree = 1 :: twoThree
• cons operator is method of right hand operand
  scala > val oneTwoThree = 1 :: 2 :: 3 :: Nil
• index operation : thrill(2)
  scala > val thrill = “Will” :: “fill” :: “until” :: Nil
  scala > thrill(2)

• create empty Scala’s list :
  scala > List()
  scala > Nil
• create a new List[String]
  scala > List(“Cool”, “tools”, “rule”)
• counts the number of list elements
  scala > val thrill = “Will” :: “fill” :: “until” :: Nil
  scala > thrill.count(s=>s.length == 4)

Reference :

1. Programming in Scala: A Comprehensive Step-by-step Guide