In this tutorial we will learn how to convert Array to Set and how to convert Set to array in Java with example and programs.
How to convert Array to Set >
- Program/Example 1.1 to convert String Array to Set in java>
- Program/Example 1.2 to convert Integer Array to Set in java >
How to convert HashSet to array in Java >
- Program/Example 2.1 to convert HashSet to String array in java>
- Program/Example 2.2 to convert HashSet to Integer array in java >
Before moving any further into this post I will like you to know bit more about List hierarchy in java - Detailed - ArrayList, LinkedList, vector classes
Set hierarchy in java - Detailed - HashSet, LinkedHashSet, TreeSet, ConcurrentSkipListSet, EnumSet classes
How to convert Array to Set >
Program/Example 1.1 to convert String Array to Set in java>
First, convert Array to List, than
pass list in constructor of HashSet
import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;
public class ConvertStringArrayToSetExample {
public static void main(String[] args) {
String stringArray[] = { "a", "b", "a" };
//First, convert Array to List
//Than pass list in constructor of HashSet
Set<String> set = new HashSet<String>(Arrays.asList(stringArray));
// Display set
System.out.println(set);
}
}
/*OUTPUT
[a, b]
*/
|
Program/Example 1.2 to convert Integer Array to Set in java >
First, convert Array to List, Than
pass list in constructor of HashSet
import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;
public class ConvertIntegerArrayToSetExample {
public static void main(String[] args) {
Integer integerArray[] = { 1, 2, 1 };
//First, convert Array to List
//Than pass list in constructor of HashSet
Set<Integer> set = new HashSet<Integer>(Arrays.asList(integerArray));
// Display set
System.out.println(set);
}
}
/*OUTPUT
[1, 2]
*/
|
So far in this tutorial we learned how to convert Array to Set and Now we will learn how to convert Set to array in Java with example and programs.
How to convert HashSet to array in Java >
Program/Example 2.1 to convert HashSet to String array in java>
First, convert set to List by passing set in constructor of ArrayList
Create stringArray of ArrayList's size
Use toArray method to convert ArrayList to Array
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
public class ConvertHashSetToStringArrayExample {
public static void main(String[] args) {
Set<String> set = new HashSet<String>();
set.add("a");
set.add("b");
//First, convert set to List
//by passing set in constructor of ArrayList
List<String> arrayList = new ArrayList<String>(set);
//Create stringArray of ArrayList's size
String[] stringArray = new String[arrayList.size()];
//Use toArray method to convert ArrayList to Array
arrayList.toArray(stringArray);
//Let's display the stringArray
System.out.println("Display the stringArray");
for(int i=0; i<stringArray.length; i++){
System.out.print(stringArray[i]+" ");
}
}
}
/*OUTPUT
Display the stringArray
a b
*/
|
Program/Example 2.2 to convert HashSet to Integer array in java >
First, convert set to List by passing set in constructor of ArrayList
Create integerArray of ArrayList's size
Use toArray method to convert ArrayList to Array
package convertArrayTo_set;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
public class ConvertHashSetToIntegerArrayExample {
public static void main(String[] args) {
Set<Integer> set = new HashSet<Integer>();
set.add(1);
set.add(2);
//First, convert set to List
//by passing set in constructor of ArrayList
List<Integer> arrayList = new ArrayList<Integer>(set);
//Create integerArray of ArrayList's size
Integer[] integerArray = new Integer[arrayList.size()];
//Use toArray method to convert ArrayList to Array
arrayList.toArray(integerArray);
//Let's display the integerArray
System.out.println("Display the integerArray");
for(int i=0; i<integerArray.length; i++){
System.out.print(integerArray[i]+" ");
}
}
}
/*OUTPUT
Display the integerArray
1 2
*/
|
So, In this tutorial we learned how to convert Array to Set and how to convert Set to array in Java with example and programs.
Having any doubt? or you you liked the tutorial! Please comment in below section.
Please express your love by liking JavaMadeSoEasy.com (JMSE) on facebook, following on google+ or Twitter.
RELATED LINKS>