Question

How to convert a map to an array in Java

Answer 1

import java.util.Map;
import java.util.Arrays;
import java.util.HashMap;

public class MyClass 
{
    public static void main(String[] args)
    {
        Map<String, String> mp = new HashMap<>();
 
        mp.put("Red", "#FF0000");
        mp.put("Green", "#00FF00");
        mp.put("Blue", "#0000FF");
        mp.put("Yellow", "#FFFF00");
 
        Object[] arr = mp.entrySet().toArray();
 
        System.out.println(Arrays.toString(arr));
    }
}


 
 
 
 
/*
run:
 
[Red=#FF0000, Blue=#0000FF, Yellow=#FFFF00, Green=#00FF00]
 
*/

 

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Answer 2

import java.util.Map;
import java.util.Arrays;
import java.util.HashMap;

public class MyClass 
{
    public static void main(String[] args)
    {
        Map<String, String> mp = new HashMap<>();
 
        mp.put("Red", "#FF0000");
        mp.put("Green", "#00FF00");
        mp.put("Blue", "#0000FF");
        mp.put("Yellow", "#FFFF00");
 
        String[] arr = mp.values().toArray(new String[0]);
 
        System.out.println(Arrays.toString(arr));
    }
}


 
 
 
 
/*
run:
 
[#FF0000, #0000FF, #FFFF00, #00FF00]
 
*/

 

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Answer 3

import java.util.Map;
import java.util.Arrays;
import java.util.HashMap;

public class MyClass 
{
    public static void main(String[] args)
    {
        Map<String, String> mp = new HashMap<>();
 
        mp.put("Red", "#FF0000");
        mp.put("Green", "#00FF00");
        mp.put("Blue", "#0000FF");
        mp.put("Yellow", "#FFFF00");
        
        String[] key = mp.keySet().toArray(new String[0]);
        System.out.println(Arrays.toString(key));

        String[] value = mp.values().toArray(new String[0]);
        System.out.println(Arrays.toString(value));
        
        for (int i = 0; i < mp.size(); i++) {
            System.out.println(key[i] + " = " + value[i]);
        }
    }
}


 
 
 
 
/*
run:
 
[Red, Blue, Yellow, Green]
[#FF0000, #0000FF, #FFFF00, #00FF00]
Red = #FF0000
Blue = #0000FF
Yellow = #FFFF00
Green = #00FF00
 
*/

 

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Answer 4

import java.util.Map;
import java.util.Arrays;
import java.util.HashMap;

public class MyClass 
{
    public static void main(String[] args)
    {
        Map<String, String> mp = new HashMap<>();
 
        mp.put("Red", "#FF0000");
        mp.put("Green", "#00FF00");
        mp.put("Blue", "#0000FF");
        mp.put("Yellow", "#FFFF00");
        
        String[] key = new String[mp.size()];
        String[] value = new String[mp.size()];

        int i = 0;
        for (Map.Entry<String, String> entry: mp.entrySet()) {
            key[i] = entry.getKey();
            value[i++] = entry.getValue();
        }
        
        System.out.println(Arrays.toString(key));
        System.out.println(Arrays.toString(value));
        
        for (i = 0; i < mp.size(); i++) {
            System.out.println(key[i] + " = " + value[i]);
        }
    }
}


 
 
 
 
/*
run:
 
[Red, Blue, Yellow, Green]
[#FF0000, #0000FF, #FFFF00, #00FF00]
Red = #FF0000
Blue = #0000FF
Yellow = #FFFF00
Green = #00FF00
 
*/

 

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