Sort list in reverse order in Kotlin

This article explores different ways to sort a mutable list in reverse order in Kotlin. The sorting would be done in-place and is stable.

1. Using `sortDescending()` function

To sort the list in reverse order, you can use the native sortDescending() function.

fun main() {

val list = mutableListOf(6, 4, 8, 7, 3)

list.sortDescending()

println(list) // [8, 7, 6, 4, 3]

}

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2. Using `sortByDescending()` function

The sortByDescending() function sorts elements of the list descending according to the sort order of the value returned by the specified selector function.

fun main() {

val list = mutableListOf(6, 4, 8, 7, 3)

list.sortByDescending { it }

println(list) // [8, 7, 6, 4, 3]

}

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3. Using `sortWith()` function

You can also sort the list according to the order specified by a comparator using the sortWith() function.

fun main() {

val list = mutableListOf(6, 4, 8, 7, 3)

list.sortWith(Comparator.reverseOrder())

println(list) // [8, 7, 6, 4, 3]

}

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You can also implement your own reverse comparator:

fun main() {

val list = mutableListOf(6, 4, 8, 7, 3)

list.sortWith(Comparator{ x, y -> y.compareTo(x) })

println(list) // [8, 7, 6, 4, 3]

}

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4. Using `sort()` function

Another plausible way to get the reversed list is to sort it first in ascending order and then reverse the sorted list.

fun main() {

val list = mutableListOf(6, 4, 8, 7, 3)

list.sort()

list.reverse()

println(list) // [8, 7, 6, 4, 3]

}

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5. Using `sortedWith()` function

Finally, if you have an immutable list instance, you can use the sortedWith() function to create a new list of elements sorted in reverse order using order induced by the specified comparator.

fun main() {

val list = listOf(6, 4, 8, 7, 3)

val sortedList = list.sortedWith(Comparator.reverseOrder())

println(sortedList) // [8, 7, 6, 4, 3]

}

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That’s all about sorting a list in reverse order in Kotlin.

Sort list in reverse order in Kotlin

1. Using sortDescending() function

2. Using sortByDescending() function

3. Using sortWith() function

4. Using sort() function

5. Using sortedWith() function

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1. Using `sortDescending()` function

2. Using `sortByDescending()` function

3. Using `sortWith()` function

4. Using `sort()` function

5. Using `sortedWith()` function