HashSet In Scala

HashSet is sealed class. It extends immutable Set and AbstractSet trait. Hash code is used to store elements. It neither sorts the elements nor maintains insertion order . The Set interface implemented by the HashSet class, backed by a hash table . In Scala, A concrete implementation of Set semantics is known HashSet.
Syntax:

var HashsetName = HashSet(element1, element2, element3, ....)  

Operations perform with HashSet

• Initialize a HashSet : Below is the example to create or initialize HashSet.
  Example :

  // Scala program of Initializing HashSet
  import scala.collection.immutable.HashSet
  
  // Creating object
  object GFG
  {
      // Main method
      def main(args:Array[String])
      {
          println("Initialize a HashSet")
  
          // Creating HashSet
          val hashSet: HashSet[String] = HashSet("Geeks",
                                      "GeeksForGeeks", "Author")
          println(s"Elements are = $hashSet")
      }
  }

  Output:

  Initialize a HashSet
  Elements are = Set(Geeks, Author, GeeksForGeeks)

• Check specific elements in HashSet :
  Example :

  // Scala program of Check specific elements in HashSet
  import scala.collection.immutable.HashSet
  
  // Creating object
  object GFG
  {
      // Main method
      def main(args:Array[String])
      {
          println("Initialize a HashSet")
  
          // Creating HashSet
          val hashSet: HashSet[String] = HashSet("Geeks",
                                  "GeeksForGeeks", "Author")
          println(s"Elements are = $hashSet")
  
          // Checking
          println(s"Element Geeks = ${hashSet("Geeks")}")
          println(s"Element Student = ${hashSet("Student")}")
      }
  }

  Output:

  Initialize a HashSet
  Elements are = Set(Geeks, Author, GeeksForGeeks)
  Element Geeks = true
  Element Student = false
  

• Adding an elements in HashSet : We can add an element in HashSet by using + sign. below is the example of adding an element in HashSet.
  Example :

  // Scala program of adding an element in HashSet
  import scala.collection.immutable.HashSet
  
  // Creating object
  object GFG
  {
      // Main method
      def main(args:Array[String])
      {
          println("Initialize a HashSet")
  
          // Creating HashSet
          val hs: HashSet[String] = HashSet("Geeks",
                              "GeeksForGeeks", "Author")
          println(s"Elements are = $hs")
  
          // Adding an element in HashSet
          val hs1: HashSet[String] = hs + "GeeksClasses"
          println(s"Adding elements to HashSet = $hs1")
      }
  }

  Output:

  Initialize a HashSet
  Elements are = Set(Geeks, Author, GeeksForGeeks)
  Adding elements to HashSet = Set(GeeksClasses, Geeks, Author, GeeksForGeeks)
  

• Adding more than one element in HashSet : We can add more than one element in HashSet by using ++ sign. below is the example of adding more than one elements in HashSet.
  Example :

  // Scala program of adding more elements in HashSet
  import scala.collection.immutable.HashSet
  
  // Creating object
  object GFG
  {
      // Main method
      def main(args:Array[String])
      {
          println("Initialize a HashSet")
  
          // Creating HashSet
          val hs: HashSet[String] = HashSet("Geeks",
                                  "GeeksForGeeks", "Author")
          println(s"Elements are = $hs")
  
          // Adding elements in HashSet
          val hs1: HashSet[String] = hs ++ HashSet[String]("Java", "Scala")
          println(s"Add more than one HashSets = $hs1")
      }
  }

  Output:

  Initialize a HashSet
  Elements are = Set(Geeks, Author, GeeksForGeeks)
  Add more than one HashSets = Set(Scala, Geeks, Author, Java, GeeksForGeeks)
  

• Remove element in HashSet : We can remove an element in HashSet by using – sign. below is the example of removing an element in HashSet.
  Example :

  // Scala program of removing element in HashSet
  import scala.collection.immutable.HashSet
  
  // Creating object
  object GFG
  {
      // Main method
      def main(args:Array[String])
      {
          println("Initialize a HashSet")
  
          // Creating HashSet
          val hs: HashSet[String] = HashSet("Geeks",
                                  "GeeksForGeeks", "Author")
          println(s"Elements are = $hs")
  
          // removing elements in HashSet
          val hs1: HashSet[String] = hs - "Geeks"
          println(s"remove element from hashset = $hs1")
      }
  }

  Output:

  Initialize a HashSet
  Elements are = Set(Geeks, Author, GeeksForGeeks)
  remove element from hashset = Set(Author, GeeksForGeeks)

• Find the intersection between two HashSets : We can find intersection between two HashSets by using & sign. below is the example of finding intersection between two HashSets.
  Example :

  // Scala program of finding the intersection between two HashSets
  import scala.collection.immutable.HashSet
  
  // Creating object
  object GFG
  {
      // Main method
      def main(args:Array[String])
      {
          println("Initialize two HashSets")
  
          // Creating two HashSet
          val hs: HashSet[String] = HashSet("Geeks",
                              "GeeksForGeeks", "Author")
          println(s"Elements of hashset1 are = $hs")
  
          val hs1: HashSet[String] = HashSet("Java",
                                      "Geeks", "Scala")
          println(s"Elements of hashset2 are = $hs1")
  
          // finding the intersection between two HashSets
          println(s"Intersection of hashSet1 and hashSet2 = ${hs & hs1}")
      }
  }

  Output:

  Initialize two HashSets
  Elements of hashset1  are = Set(Geeks, Author, GeeksForGeeks)
  Elements of hashset2 are = Set(Scala, Geeks, Java)
  Intersection of hashSet1 and hashSet2 = Set(Geeks)
  

• Initializing an empty HashSet :
  Example :

  // Scala program of  Initializing an empty HashSet
  import scala.collection.immutable.HashSet
  
  // Creating object
  object GFG
  {
      // Main method
      def main(args:Array[String])
      {
          // Initializing an empty HashSet
          val emptyHashSet: HashSet[String] = HashSet.empty[String]
          println(s"Empty HashSet = $emptyHashSet")
      }
  }

  Output:

  Empty HashSet = Set()