Scala中的HashSet

HashSet是密封类。它扩展了不可变的 Set 和 AbstractSet 特征。哈希码用于存储元素。它既不排序元素也不维护插入顺序。由 HashSet 类实现的 Set 接口，由哈希表支持。在 Scala 中，Set 语义的具体实现称为 HashSet。
句法：

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

使用 HashSet 执行的操作

• 初始化 HashSet ：下面是创建或初始化 HashSet 的示例。
  例子 ：

  // 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")
      }
  } 
  

  输出：

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

• 检查 HashSet 中的特定元素：
  例子 ：

  // 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")}")
      }
  } 
  

  输出：

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

• 在 HashSet 中添加元素：我们可以使用 + 号在 HashSet 中添加元素。下面是在 HashSet 中添加元素的示例。
  例子 ：

  // 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")
      }
  }
  

  输出：

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

• 在 HashSet 中添加多个元素：我们可以使用 ++ 符号在 HashSet 中添加多个元素。下面是在 HashSet 中添加多个元素的示例。
  例子 ：

  // 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")
      }
  }
  

  输出：

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

• 移除HashSet中的元素：我们可以使用-符号移除HashSet中的元素。下面是在 HashSet 中删除元素的示例。
  例子 ：

  // 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")
      }
  }
  

  输出：

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

• 查找两个 HashSet 之间的交集：我们可以使用 & 符号找到两个 HashSet 之间的交集。下面是查找两个 HashSet 之间的交集的示例。
  例子 ：

  // 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}")
      }
  }
  

  输出：

  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)
  

• 初始化一个空的 HashSet ：
  例子 ：

  // 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")
      }
  }
  

  输出：

  Empty HashSet = Set()