It's slowly to form an object array inward decreasing or contrary order, simply provide the Comparator alongside opposite order. You tin terminate fifty-fifty role Collections.reverseOrder() if yous desire to form array inward the decreasing order, which returns a contrary Comparator to form objects inward the gild opposite of their natural ordering defined past times the compareTo() method. Unfortunately, for a primitive array, at that topographic point is no straight means to form inward descending order. The Arrays.sort() method which is used to form a primitive array inward Java doesn't convey a boolean to form the primitive array inward contrary order. You powerfulness direct maintain seen the error "no suitable method works life for sort(int[],comparator<object>)" which occurs when programmers endeavor to telephone telephone the Arrays.sort() method past times passing contrary Comparator defined past times Collection.reverseOrder(). That volition operate fine alongside Integer array but volition non operate alongside an int array. The solely means to form a primitive array inward descending gild is, get-go form the array inward ascending gild in addition to hence contrary the array inward house equally shown here. This is likewise truthful for two-dimensional primitive arrays.
Fortunately, yous don't postulate to code it yourself, yous tin terminate role Collections.reverseOrder(Comparator comp) to acquire a contrary gild Comparator. Just exceed your Comparator to this method in addition to it volition render the opposite gild Comparator.
If yous are using Comparator method to form inward natural order, yous tin terminate likewise role the overloaded Collection.reverseOrder() method. It returns a Comparator which sorts inward the opposite of natural order. In fact, this is the 1 yous volition live using most of the time.
Here is an instance of sorting Integer array inward descending order:
Now the cubes array volition live {256, 125, 64, 27,8}, you tin terminate encounter the gild is reversed in addition to elements are sorted inward decreasing order. Sometimes, yous role your ain customized Comparator e.g. a comparator nosotros direct maintain used to form Employee past times their salary. If yous are using that 1 hence yous postulate to telephone telephone the Array.sort() method equally follows
where SALARY_CPM is the Comparator which orders employee past times their salary. You tin terminate encounter the Core Java Volume 1 - Fundamentals past times Cay S. Horstmann to larn to a greater extent than nearly how to form objects inward Java.
This is compile fourth dimension error "The method sort(int[]) inward the type Arrays is non applicable for the arguments (int[], Comparator<Object>)" because at that topographic point is no such method inward the java.util.Arrays class.
The solely means to form a primitive array inward descending gild is get-go to form it inward ascending gild in addition to hence reverse the array inward place equally shown here. Since inward house reversal is an efficient algorithm in addition to doesn't require extra memory, yous tin terminate role it form in addition to contrary large array equally well. You tin terminate likewise encounter a proficient mass on information construction in addition to algorithm e.g. Introduction to Algorithms to larn to a greater extent than nearly efficient sorting algorithm e.g. O(n) sorting algorithm similar Bucket sort.
I direct maintain used Arrays.sort() method to form a primitive array inward ascending gild in addition to hence written a reverse() method to contrary the array inward place. Since at that topographic point are viii primitive types inward Java, yous postulate to write divide contrary methods to contrary a byte array, long array or a float array.
That's all nearly how to form an array inward descending gild inward Java. You tin terminate role a contrary Comparator or Collections.reverseOrder() method to form an object array inward descending gild e.g. String array, Integer array or Double array. The Arrays.sort() method is overloaded to convey a Comparator, which tin terminate likewise live a contrary Comparator. Now, to form a primitive array inward decreasing order, at that topographic point is no straight way. You get-go postulate to form it on ascending or normal gild in addition to hence contrary the array inward place. The in-place algorithm is an efficient means to contrary array in addition to doesn't require extra memory, hence it tin terminate likewise live used to contrary a large array.
Other Java array tutorials yous may like:
How to form object array inward descending order
First, let's encounter the instance of sorting an object array into ascending order. Then we'll encounter how to form a primitive array inward descending order. In gild to form a reference type array e.g. String array, Integer array or Employee array, yous postulate to exceed the Array.sort() method a reverse Comparator.Fortunately, yous don't postulate to code it yourself, yous tin terminate role Collections.reverseOrder(Comparator comp) to acquire a contrary gild Comparator. Just exceed your Comparator to this method in addition to it volition render the opposite gild Comparator.
If yous are using Comparator method to form inward natural order, yous tin terminate likewise role the overloaded Collection.reverseOrder() method. It returns a Comparator which sorts inward the opposite of natural order. In fact, this is the 1 yous volition live using most of the time.
Here is an instance of sorting Integer array inward descending order:
Integer[] cubes = new Integer[] { 8, 27, 64, 125, 256 }; Arrays.sort(cubes, Collections.reverseOrder());
Now the cubes array volition live {256, 125, 64, 27,8}, you tin terminate encounter the gild is reversed in addition to elements are sorted inward decreasing order. Sometimes, yous role your ain customized Comparator e.g. a comparator nosotros direct maintain used to form Employee past times their salary. If yous are using that 1 hence yous postulate to telephone telephone the Array.sort() method equally follows
Arrays.sort(emp[], Collections.sort(SALARY_CMP));
where SALARY_CPM is the Comparator which orders employee past times their salary. You tin terminate encounter the Core Java Volume 1 - Fundamentals past times Cay S. Horstmann to larn to a greater extent than nearly how to form objects inward Java.
How to form primitive array inward descending order
Now, let's encounter how to sort a primitive array e.g. int[], long[], float[] or char[] inward descending order. As I told, at that topographic point are no Arrays.sort() method which tin terminate form the array inward the contrary order. Many programmers brand fault of calling the inward a higher house Array.sort() method equally follows:int[] squares = { 4, 25, 9, 36, 49 }; Arrays.sort(squares, Collections.reverseOrder());
This is compile fourth dimension error "The method sort(int[]) inward the type Arrays is non applicable for the arguments (int[], Comparator<Object>)" because at that topographic point is no such method inward the java.util.Arrays class.
The solely means to form a primitive array inward descending gild is get-go to form it inward ascending gild in addition to hence reverse the array inward place equally shown here. Since inward house reversal is an efficient algorithm in addition to doesn't require extra memory, yous tin terminate role it form in addition to contrary large array equally well. You tin terminate likewise encounter a proficient mass on information construction in addition to algorithm e.g. Introduction to Algorithms to larn to a greater extent than nearly efficient sorting algorithm e.g. O(n) sorting algorithm similar Bucket sort.
Java Program to contrary an array inward descending order
Here is consummate Java computer program to form an object array in addition to a primitive array inward the contrary gild inward Java. As I told it's slowly to form a reference array to decreasing gild because yous tin terminate provide a contrary Comparator past times using Collections.reverseOrder() method, but it's tricky to form the primitive array inward contrary order. The solely means to compass that is get-go past times sorting the array inward increasing order in addition to hence reverse the array inward place in addition to that what I direct maintain done inward this example.I direct maintain used Arrays.sort() method to form a primitive array inward ascending gild in addition to hence written a reverse() method to contrary the array inward place. Since at that topographic point are viii primitive types inward Java, yous postulate to write divide contrary methods to contrary a byte array, long array or a float array.
import java.util.Arrays; import java.util.Collections; /* * Java Program to form the array inward descending order. * Object array tin terminate live sorted inward contrary gild past times using * Array.sort(array, Comparator) method but primitive * array e.g. int[] or char[] tin terminate solely live sorted * inward ascending order. For opposite order, simply * contrary the array. * */ public class ArraySorter { public static void main(String[] args) { // sorting Integer array inward descending order Integer[] cubes = new Integer[] { 8, 27, 64, 125, 256 }; System.out.println("Integer array earlier sorting : " + Arrays.toString(cubes)); System.out.println("sorting array inward descending order"); Arrays.sort(cubes, Collections.reverseOrder()); System.out.println("array afterwards sorted inward contrary order: " + Arrays.toString(cubes)); // sorting primitive array int[] inward descending order int[] squares = { 4, 25, 9, 36, 49 }; System.out.println("int[] array earlier sorting : " + Arrays.toString(squares)); System.out.println("sorting array inward ascending order"); Arrays.sort(squares, Collections.reverseOrder()); System.out.println("reversing array inward place"); reverse(squares); System.out.println("Sorted array inward descending gild : " + Arrays.toString(squares)); } /** * contrary given array inward house * * @param input */ public static void reverse(int[] input) { int last = input.length - 1; int middle = input.length / 2; for (int i = 0; i <= middle; i++) { int temp = input[i]; input[i] = input[last - i]; input[last - i] = temp; } } } Output Integer array earlier sorting : [8, 27, 64, 125, 256] sorting array in descending gild array afterwards sorted in reverse order: [256, 125, 64, 27, 8] int[] array earlier sorting : [4, 25, 9, 36, 49] sorting an array in ascending gild reversing array in house Sorted array in descending gild : [49, 36, 25, 9, 4]
That's all nearly how to form an array inward descending gild inward Java. You tin terminate role a contrary Comparator or Collections.reverseOrder() method to form an object array inward descending gild e.g. String array, Integer array or Double array. The Arrays.sort() method is overloaded to convey a Comparator, which tin terminate likewise live a contrary Comparator. Now, to form a primitive array inward decreasing order, at that topographic point is no straight way. You get-go postulate to form it on ascending or normal gild in addition to hence contrary the array inward place. The in-place algorithm is an efficient means to contrary array in addition to doesn't require extra memory, hence it tin terminate likewise live used to contrary a large array.
Other Java array tutorials yous may like:
- How to declare in addition to initialize a two-dimensional array inward Java? (solution)
- How to convert an array to String inward Java? (solution)
- How to evidence if an array contains a value inward Java? (solution)
- 22 Array concepts Interview Questions inward Java? (answer)
- How to impress elements of an array inward Java? (example)
- What is the divergence betwixt array in addition to ArrayList inward Java? (answer)
- How to loop over an array inward Java? (solution)
- How to detect duplicate elements inward Java array? (answer)
- How to withdraw duplicate objects from an array inward Java? (answer)
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