In this article, we will discuss how to sort Arrays in both ascending and descending order
1. Sorting Arrays in Ascending order :
- Passing original/actual arrays to Arrays.sort() methods sorts elements in ascending order
- Below is the method signature of sort() method from Arrays class
Method Signature:
public static void sort(int[] i);
public static void sort(obj[] a);
SortingArrayInAscendingOrder.java
package in.bench.resources.java.arrays.sorting;
import java.util.Arrays;
public class SortingArrayInAscendingOrder {
public static void main(String[] args) {
// sample int[] array
Integer[] intArray = {
1975,
2003,
1979,
1992,
1983,
1999,
1987
};
// before sorting
System.out.println("Integer[] Array -"
+ " before sorting : ");
for(Integer iValue : intArray) {
System.out.println(iValue);
}
// sorting int[] array in ascending order
Arrays.sort(intArray);
// after sorting
System.out.println("\nInteger[] Array -"
+ " after sorting in ascending order : ");
for(Integer iValue : intArray) {
System.out.println(iValue);
}
// sample String[] array
String[] strArray = {
"Clive",
"Kapil",
"Allan",
"Imran",
"Arjuna",
"Steve",
"Ricky"
};
// before sorting
System.out.println("\n\n\nString[] Array -"
+ " before sorting : \n");
for(String str : strArray) {
System.out.println(str);
}
// sorting String[] array in ascending order
Arrays.sort(strArray);
// after sorting
System.out.println("\nString[] Array -"
+ " after sorting in ascending order : \n");
for(String str : strArray) {
System.out.println(str);
}
}
}
Output:
Integer[] Array - before sorting :
1975
2003
1979
1992
1983
1999
1987
Integer[] Array - after sorting in ascending order :
1975
1979
1983
1987
1992
1999
2003
String[] Array - before sorting :
Clive
Kapil
Allan
Imran
Arjuna
Steve
Ricky
String[] Array - after sorting in ascending order :
Allan
Arjuna
Clive
Imran
Kapil
Ricky
Steve
2. Sorting Array in Descending order :
- There is an another variants of sort() method which accepts 2 input-arguments where,
- 1st argument is the original/actual arrays to be sorted
- 2nd argument is the Comparator object for custom sorting and in this case it is descending order sorting
- Below is the method signature of sort() method from Arrays class
Method Signature:
public static void sort(int[] i, Collection.reverseOrder());
public static void sort(obj[] a, Collection.reverseOrder());
SortingArrayInDescendingOrder.java
package in.bench.resources.java.arrays.sorting;
import java.util.Arrays;
import java.util.Collections;
public class SortingArrayInDescendingOrder {
public static void main(String[] args) {
// sample int[] array
Integer[] intArray = {
1975,
2003,
1979,
1992,
1983,
1999,
1987
};
// before sorting
System.out.println("Integer[] Array -"
+ " before sorting : ");
for(Integer iValue : intArray) {
System.out.println(iValue);
}
// sorting int[] array in descending order
Arrays.sort(intArray, Collections.reverseOrder());
// after sorting
System.out.println("\nInteger[] Array -"
+ " after sorting in descending order : ");
for(Integer iValue : intArray) {
System.out.println(iValue);
}
// sample String[] array
String[] strArray = {
"Clive",
"Kapil",
"Allan",
"Imran",
"Arjuna",
"Steve",
"Ricky"
};
// before sorting
System.out.println("\n\n\nString[] Array -"
+ " before sorting : \n");
for(String str : strArray) {
System.out.println(str);
}
// sorting String[] array in descending order
Arrays.sort(strArray, Collections.reverseOrder());
// after sorting
System.out.println("\nString[] Array -"
+ " after sorting in descending order : \n");
for(String str : strArray) {
System.out.println(str);
}
}
}
Output:
Integer[] Array - before sorting :
1975
2003
1979
1992
1983
1999
1987
Integer[] Array - after sorting in descending order :
2003
1999
1992
1987
1983
1979
1975
String[] Array - before sorting :
Clive
Kapil
Allan
Imran
Arjuna
Steve
Ricky
String[] Array - after sorting in descending order :
Steve
Ricky
Kapil
Imran
Clive
Arjuna
Allan
Note: we need to convert primitive int data-type to Integer wrapper-type by auto-boxing feature introduced in Java 1.5 version, when we pass Comparator object as 2nd argument for reverse order sorting
Hope, you found this article very helpful. If you have any suggestion or want to contribute any other way or tricky situation you faced during Interview hours, then share with us. We will include that code here.
References:
- https://docs.oracle.com/javase/7/docs/api/java/util/Arrays.html
- https://docs.oracle.com/javase/6/docs/api/java/lang/Integer.html
- https://docs.oracle.com/javase/7/docs/api/java/lang/Integer.html
- https://docs.oracle.com/javase/8/docs/api/java/lang/Integer.html
- https://docs.oracle.com/javase/tutorial/java/data/strings.html
- https://docs.oracle.com/javase/6/docs/api/java/lang/String.html
- https://docs.oracle.com/javase/7/docs/api/java/lang/String.html
- https://docs.oracle.com/javase/8/docs/api/java/lang/String.html
- https://docs.oracle.com/javase/tutorial/java/nutsandbolts/datatypes.html
Happy Coding !!
Happy Learning !!
