In this article, we will show how to convert the values of a Map to an Array, a List or a Set using Java.
1. Convert Map Values to Array
First, let’s look at converting the values of the Map into an array, using plain java:
package net.javaguides.hibernate;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
public class MapToArrayListSetExample {
public String[] mapValuesToArray(Map < Integer, String > sourceMap) {
Collection < String > values = sourceMap.values();
String[] targetArray = values.toArray(new String[values.size()]);
return targetArray;
}
public static void main(String[] args) {
MapToArrayListSetExample arrayListSetExample = new MapToArrayListSetExample();
Map < Integer, String > sourceMap = new HashMap < > ();
sourceMap.put(100, "ABC");
sourceMap.put(101, "PQR");
sourceMap.put(102, "XYZ");
String[] targetArray = arrayListSetExample.mapValuesToArray(sourceMap);
System.out.println(Arrays.toString(targetArray));
}
}
Output:
[ABC, PQR, XYZ]
2. Convert Map Values to List
let’s write a Java program to convert Map values to List:
package net.javaguides.hibernate;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class MapValuesToListExample {
public List < String > mapValuesToList(Map < Integer, String > sourceMap) {
List < String > targetList = new ArrayList < > (sourceMap.values());
return targetList;
}
public static void main(String[] args) {
MapValuesToListExample arrayListSetExample = new MapValuesToListExample();
Map < Integer, String > sourceMap = new HashMap < > ();
sourceMap.put(100, "ABC");
sourceMap.put(101, "PQR");
sourceMap.put(102, "XYZ");
List < String > targetList = arrayListSetExample.mapValuesToList(sourceMap);
System.out.println(targetList.toString());
}
}
Output:
[ABC, PQR, XYZ]
3. Convert Map Values to Set
let’s write a Java program to convert Map values to Set:
package net.javaguides.hibernate;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
public class MapValuesToSetExample {
public Set < String > mapValuesToList(Map < Integer, String > sourceMap) {
Set < String > targetList = new HashSet < > (sourceMap.values());
return targetList;
}
public static void main(String[] args) {
MapValuesToSetExample arrayListSetExample = new MapValuesToSetExample();
Map < Integer, String > sourceMap = new HashMap < > ();
sourceMap.put(100, "ABC");
sourceMap.put(101, "PQR");
sourceMap.put(102, "XYZ");
Set < String > targetList = arrayListSetExample.mapValuesToList(sourceMap);
System.out.println(targetList.toString());
}
}
Output:
[ABC, PQR, XYZ]
Comments
Post a comment