Skip to content
Related Articles

Related Articles

Improve Article
Sets union() function | Guava | Java
  • Last Updated : 15 Nov, 2018

Guava’s Sets.union() returns an unmodifiable view of the union of two sets. The returned set contains all elements that are contained in either backing set. Iterating over the returned set iterates first over all the elements of set1, then over each element of set2, in order, that is not contained in set1.

Syntax:

public static <E> 
  Sets.SetView<E> 
    union(Set<? extends E> set1, 
          Set<? extends E> set2)

Return Value: This method returns an unmodifiable view of the union of two sets.

Example 1:




// Java code to show implementation
// of Guava's Sets.union() method
  
import com.google.common.collect.Sets;
import java.util.Set;
  
class GFG {
  
    // Driver's code
    public static void main(String[] args)
    {
        // Creating first set
        Set<Integer>
            set1 = Sets.newHashSet(1, 2, 3, 4, 5);
  
        // Creating second set
        Set<Integer>
            set2 = Sets.newHashSet(3, 5, 7, 9);
  
        // Using Guava's Sets.union() method
        Set<Integer>
            answer = Sets.union(set1, set2);
  
        // Displaying the union of set set1 and set2
        System.out.println("Set 1: "
                           + set1);
        System.out.println("Set 2: "
                           + set2);
        System.out.println("Set 1 union Set 2: "
                           + answer);
    }
}
Output:



Set 1: [1, 2, 3, 4, 5]
Set 2: [9, 3, 5, 7]
Set 1 union Set 2: [1, 2, 3, 4, 5, 9, 7]

Example 2:




// Java code to show implementation
// of Guava's Sets.union() method
  
import com.google.common.collect.Sets;
import java.util.Set;
  
class GFG {
  
    // Driver's code
    public static void main(String[] args)
    {
        // Creating first set
        Set<String>
            set1 = Sets.newHashSet("G", "e", "e", "k", "s");
  
        // Creating second set
        Set<String>
            set2 = Sets.newHashSet("g", "f", "G", "e");
  
        // Using Guava's Sets.union() method
        Set<String>
            answer = Sets.union(set1, set2);
  
        // Displaying the union of set set1 and set2
        System.out.println("Set 1: "
                           + set1);
        System.out.println("Set 2: "
                           + set2);
        System.out.println("Set 1 union Set 2: "
                           + answer);
    }
}
Output:
Set 1: [k, s, e, G]
Set 2: [e, f, g, G]
Set 1 union Set 2: [k, s, e, G, f, g]

Attention reader! Don’t stop learning now. Get hold of all the important Java Foundation and Collections concepts with the Fundamentals of Java and Java Collections Course at a student-friendly price and become industry ready. To complete your preparation from learning a language to DS Algo and many more,  please refer Complete Interview Preparation Course.




My Personal Notes arrow_drop_up
Recommended Articles
Page :