Gist: Scala Set

In Scala, an instance of Set can be declared as follows.

val s = (1 to 6).toSet

Principle difference between sets and sequences are three:

• Sets are unordered

val s = (1 to 6).toSet
//> s : scala.collection.immutable.Set[Int] = Set(5, 1, 6, 2, 3, 4)

• Sets do not have duplicate elements

s map (_ % 2 ==0)
//> res8: scala.collection.immutable.Set[Boolean] = Set(false, true)

• The fundamental operation on set is contains.

s contains 5
//> res9: Boolean = true