The toArray() method of Java Set is used to form an array of the same elements as that of the Set. Basically, it copies all the element from a Set to a new array.
Syntax:
Object[] toArray()
Parameters: The method takes optional parameter. If we provide the type of Object array we want we can pass it as an argument. for ex: set.toArray(new Integer[0]) returns an array of type Integer, we can also do it as set.toArray(new Integer[size]) where size is the size of the resultant array. Doing it in the former way works as the required size is allocated internally.
Return Value: The method returns an array containing the elements similar to the Set.
Below programs illustrate the Set.toArray() method:
Program 1:
Java
// Java code to illustrate toArray()import java.util.*;public class SetDemo { public static void main(String args[]) { // Creating an empty Set Set<String> abs_col = new HashSet<String>(); // Use add() method to add // elements into the Set abs_col.add("Welcome"); abs_col.add("To"); abs_col.add("Geeks"); abs_col.add("For"); abs_col.add("Geeks"); // Displaying the Set System.out.println("The Set: " + abs_col); // Creating the array and using toArray() Object[] arr = abs_col.toArray(); System.out.println("The array is:"); for (int j = 0; j < arr.length; j++) System.out.println(arr[j]); }} |
The Set: [Geeks, For, Welcome, To] The array is: Geeks For Welcome To
Program 2:
Java
// Java code to illustrate toArray()import java.util.*;public class SetDemo { public static void main(String args[]) { // Creating an empty Set Set<Integer> abs_col = new HashSet<Integer>(); // Use add() method to add // elements into the Set abs_col.add(10); abs_col.add(15); abs_col.add(30); abs_col.add(20); abs_col.add(5); abs_col.add(25); // Displaying the Set System.out.println("The Set: " + abs_col); // Creating the array and using toArray() Integer[] arr = abs_col.toArray(new Integer[0]); System.out.println("The array is:"); for (int j = 0; j < arr.length; j++) System.out.println(arr[j]); }} |
The Set: [20, 5, 25, 10, 30, 15] The array is: 20 5 25 10 30 15
Reference: https://docs.oracle.com/javase/7/docs/api/java/util/Set.html#toArray()
