Java Set to Array

In this tutorial we will learn about  how to convert java Set to array . We will discuss different example of Set to array conversion using toArray() method , native method (iteration of Set) and java8 .

Convert Set to Array in Java

Let’s discuss different method for how to convert TreeSet to array in java using toArray() method , Using Java8 stream and Native method .

 1. Java Set to array Using toArray() Method

Now , We will see how to convert TreeSet to array in java with the help of toArray() method . toArray() method returns an array containing all of the elements in this collection. toArray() method return array of object.

Syntax

public Object[] toArray() {

   }

In this approach we will convert Set to array using Set.toArray() method in java method . This is easiest approach .  Set.toArray() method returns an array containing all of the elements in this collection. We will create TreeSet and add element into it using add() method . Then we will use set.toArray() method on TreeSet and it returns array of elements of Set.

import java.util.Set;
import java.util.TreeSet;

public class SetToArray {

	public static void main(String[] args) {

		// Constructs a new, empty set
		Set<String> set = new TreeSet<String>();

		// add element in it
		set.add("java");
		set.add("php");
		set.add("android");

		// display the element Of Set
		System.out.println("Set Elements : " + set);

		/*
		 * Returns an array containing all of the elements in this collection
		 */
		Object[] array = set.toArray();

		// print object type array
		for (Object object : array) {
			System.out.println("Array Element : "+object);
		}

	}

}

Output:

Set Elements : [android, java, php]
Array Element : android
Array Element : java
Array Element : php

2. Convert Set to array – Iterate Set

In this Approach we will create Set and add some elements into it and create a array of Set size . Then we will iterate Set element and add them to array one by one as per given below java program.

import java.util.Set;
import java.util.TreeSet;

public class SetToArray1 {
	
	public static void main(String[] args) {
		
		
		   //Constructs a new, empty set
		   Set<String>	Set = new TreeSet<String>();
		   
		   //add element in it 
		   Set.add("java");
		   Set.add("php");
		   Set.add("android");
		   
		   //display the element of Set
		   System.out.println("Set Elements : "+ Set);
		
		   String [] arr = new String[Set.size()];
		   
		   int i =0;
		   for (String element : Set) {
			arr[i++] = element;
		   }

		   //print array Element
		   for (String element : arr) {
			System.out.println("Array Element is : "+element);
		}

	}

}

Output:

Set Elements : [android, java, php]
Array Element is : android
Array Element is : java
Array Element is : php

In this article we have learned about how to convert set to array in java. You can see more java TreeSet program for practice .

Reference :

A Guide To TreeSet                                                                                                              Java Doc – TreeSet

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