How do I convert Map to Array in Java

Published May 16, 2022

Rather than declaring separate variables for each item, you can store multiple values in an array by converting a map to an array. A Map consists of a key and a value pair. Among the list objects, it can contain key values while the other can contain map values separately.

How to convert a Map to Array in Java

Here are the simple steps you need to follow to convert a map to a list:

• Step 1: First, create the Map object.

• Step 2: Input elements into it as key-value pairs by calling the put() method

• Step 3: For the keys of the map, create an ArrayList of integer type. Call keySet() of the Map class in its constructor.

• Step 4: Assign the values of the map to an ArrayList of String type. Call the values() method of the Map class in its constructor.

• Step 5: Lastly, print the results of both lists.

 

Example

In this example we are going to follow the above steps to convert Map to an Array

import java.util.ArrayList; import java.util.HashMap; import java.util.Map; public class Convert_Map_to_Array {             public static void main(String[] args) {                         Map<Integer, String> ManMap = new HashMap<>();                         ManMap.put(20, "Python");                         ManMap.put(30, "Java");                         ManMap.put(50, "Ruby");                         ManMap.put(60, "Python");                   ArrayList<Integer> keyList = new ArrayList<Integer>(ManMap.keySet());                   ArrayList<String> valueList = new ArrayList<String>(ManMap.values());                   System.out.println("Map content ::"+keyList);                   System.out.println("Arraylist ::"+valueList);               } }

 

Output:

Map content ::[50, 20, 60, 30] Arraylist ::[Ruby, Python, Python, Java]

 

Keywords: How to convert a Map to Array in Java , Java Collections, Java