Kotlin List sortedWith()
Syntax & Examples

Syntax of List.sortedWith()

The syntax of List.sortedWith() extension function is:

fun <T> Iterable<T>.sortedWith( comparator: Comparator<in T> ): List<T>

This sortedWith() extension function of List returns a list of all elements sorted according to the specified comparator.

✐ Examples

1 Example

In this example,

We create a list named list containing the strings ['banana', 'apple', 'cherry'].
We call the sortedWith function on list, sorting the elements according to the length of each string.
The result, which is the sorted list ['apple', 'banana', 'cherry'], is stored in sortedList.
Finally, we print the sortedList to standard output using the println function.

Kotlin Program

fun main(args: Array<String>) {
    val list = listOf("banana", "apple", "cherry");
    val sortedList = list.sortedWith(compareBy { it.length });
    println(sortedList);
}

Output

[apple, banana, cherry]

2 Example

In this example,

We define a data class Person with name and age properties.
We create a list named people containing instances of Person.
We call the sortedWith function on people, sorting the elements according to the age property of each Person object.
The result, which is the sorted list of Person objects by age, is stored in sortedPeople.
Finally, we print the sortedPeople to standard output using the println function.

Kotlin Program

fun main(args: Array<String>) {
    data class Person(val name: String, val age: Int)
    val people = listOf(Person("Alice", 29), Person("Bob", 35), Person("Charlie", 25));
    val sortedPeople = people.sortedWith(compareBy { it.age });
    println(sortedPeople);
}

Output

[Person(name=Charlie, age=25), Person(name=Alice, age=29), Person(name=Bob, age=35)]

3 Example

In this example,

We create a list named list containing the integers [3, 1, 4, 1, 5, 9, 2, 6].
We call the sortedWith function on list, sorting the elements in ascending order.
The result, which is the sorted list [1, 1, 2, 3, 4, 5, 6, 9], is stored in sortedList.
Finally, we print the sortedList to standard output using the println function.

Kotlin Program

fun main(args: Array<String>) {
    val list = listOf(3, 1, 4, 1, 5, 9, 2, 6);
    val sortedList = list.sortedWith(compareBy { it });
    println(sortedList);
}

Output

[1, 1, 2, 3, 4, 5, 6, 9]

Summary

In this Kotlin tutorial, we learned about sortedWith() extension function of List: the syntax and few working examples with output and detailed explanation for each example.