How to iterate Set in Java
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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