Kotlin Array - sortDescending() Function

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The Kotlin array sortDescending() function is used to sort the elements of an array in place, arranging them in descending order according to their natural sort order.

This function also takes an optional parameterrangecontaining two values fromIndex, and toIndex.

The sort is stable. It means that equal elements preserve their order relative to each other after sorting.

Exception

Following are the exceptions −

• IndexOutOfBoundsException − If fromIndex is less than zero or toIndex is greater than the size of this array.

• IllegalArgumentException − If fromIndex is greater than toIndex.

Syntax

Following is the syntax of Kotlin array sortDescending() function −

fun <T : Comparable<T>> Array<out T>.sortDescending()

Parameters

This function accepts following parameters −

• fromIndex − it represent start of the range (inclusive) to sort.

• toIndex − it represent end of the range (exclusive) to sort.

Return value

This function returns an array in sorting array.

Example 1

The following is a basic example to demonstrate the use of sortDescending() function −

fun main(args: Array<String>){
   var arr = arrayOf<Int>(2, 4, 5, 6, 1)
        
   arr.sortDescending()   
   println("descending array")
   for (i in 0 until arr.size){
      println(arr.get(i))
   }   
}

Output

The above code generate following output −

descending array
6
5
4
2
1

Example 2

Now here, we create an array of string. We then use sortDescending() function to sort the elements in descending order according to alphabet −

fun main(args: Array<String>){
   var arr = arrayOf<String>("This", "is", "tutorialspoint", "India")
        
   arr.sortDescending()   
   println("Descending order:")
   for (i in 0 until arr.size){
      println(arr.get(i))
   }
}

Output

Following is the output −

Descending order:
tutorialspoint
is
This
India

Example 3

The below example uses sortDescending() function with specific range to modify some of array element in descending order −

fun main(args: Array<String>){
   var arr = arrayOf<Char>('t', 'u', 't', 'o', 'r', 'i', 'a', 'l', 's', 'p', 'o', 'i', 'n', 't')
   
   // sort the array
   arr.sortDescending(3, 7)   
   println("Descending order:")
   println(arr.joinToString())
}

Output

Following is the output −

Descending order:
t, u, t, r, o, i, a, l, s, p, o, i, n, t