How to iterate Set in Java

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Last updated on February 27th, 2024

In this topic, we will learn to iterate the Set in Java. A Set is an interface that is available in java.util package. These are the following ways to iterate the Set:
• Iterate Set Using Iterator
• Iterate Set Using for each loop
• Iterate Set using Lambda Expression
• Iterate Set using stream.forEach() method

Iterate Set Using Iterator

Example

import java.util.Set;
import java.util.HashSet;
import java.util.Iterator;

public class Test {
  public static void main(String[] args) {
    //Creating a Set
    Set<String> names = new HashSet<>();
    names.add("Rim");
    names.add("Sim");
    names.add("Kim");
    System.out.println("Set: " + names);

    //Creating an instance of Iterator
    Iterator<String> iterate = names.iterator();
    System.out.println("Iterating over Set:");
    while(iterate.hasNext()) {
      System.out.println(iterate.next());
    }
  }
}

Output

Set: [Sim, Rim, Kim]
Iterating over Set:
Sim
Rim
Kim

Iterate Set Using for each loop

Example

import java.util.Set;
import java.util.HashSet;
import java.util.Iterator;

public class Test {
  public static void main(String[] args) {
    //Creating a Set
    Set<String> names = new HashSet<>();
    names.add("Rim");
    names.add("Sim");
    names.add("Kim");
    System.out.println("Set: " + names);
    System.out.println("Iterating over Set:");
    for(String name:names) {
      System.out.println(name);
    }
  }
}

Output

Set: [Sim, Rim, Kim]
Iterating over Set:
Sim
Rim
Kim

Iterate Set using Lambda Expression

Example

import java.util.Set;
import java.util.HashSet;
import java.util.Iterator;

public class Test {
  public static void main(String[] args) {
    // Creating a Set
    Set<String> names = new HashSet<>();
    names.add("Rim");
    names.add("Sim");
    names.add("Kim");
    System.out.println("Set: " + names);
    System.out.println("Iterating over Set:");
    names.forEach(
    (name) -> { System.out.println(name); });
  }
}

Output

Set: [Sim, Rim, Kim]
Iterating over Set:
Sim
Rim
Kim

Iterate Set using stream.forEach() method

Example

import java.util.Set;
import java.util.HashSet;
import java.util.Iterator;

public class Test {
  public static void main(String[] args) {
    //Creating a Set
    Set<String> names = new HashSet<>();
    names.add("Rim");
    names.add("Sim");
    names.add("Kim");
    System.out.println("Set: " + names);
    System.out.println("Iterating over Set:");
    //UsingforEach() method 
    names.stream().forEach((name) -> {
      System.out.println(name);
    });
  }
}

Output

Set: [Sim, Rim, Kim]
Iterating over Set:
Sim
Rim
Kim

Conclusion

In this topic, we learnt how to iterate the Set in several ways in Java.

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