Scala 不可变 TreeSet +() 方法

在 Scala 不可变TreeSet class中， +()方法用于将元素添加到 TreeSet，除非它已经存在。

Method Definition: def +(elem: A): TreeSet[A]

Return Type: It returns a new TreeSet with an additional element unless the element is already present.

示例 #1：

// Scala program of +() 
// method 
  
// Import TreeSet
import scala.collection.immutable._
  
// Creating object 
object GfG 
{ 
  
    // Main method 
    def main(args:Array[String]) 
    { 
      
        // Creating TreeSets
        val t1 = TreeSet("a", "e", "i", "o") 
          
        // Print the TreeSets
        println(t1) 
          
        // Applying +() method  
        val result = t1 + ("u")
          
        // Display output 
        print("After adding an element: " + result) 
           
    } 
} 

输出：

TreeSet(a, e, i, o)
After adding an element: TreeSet(a, e, i, o, u)

示例 #2：

// Scala program of +() 
// method 
  
// Import TreeSet
import scala.collection.immutable._
  
// Creating object 
object GfG 
{ 
  
    // Main method 
    def main(args:Array[String]) 
    { 
      
        // Creating TreeSets
        val t1 = TreeSet(2, 1, 5, 4, 1) 
          
        // Print the TreeSets
        println(t1) 
          
        // Applying +() method  
        val result = t1 + (3)
          
        // Display output 
        print("After adding an element: " + result) 
           
    } 
} 

输出：

TreeSet(1, 2, 4, 5)
After adding an element: TreeSet(1, 2, 3, 4, 5)