Kotlin Array - toList() Function

The Kotlin array toList() function is used to convert an array into a list. This function creates a new list instance containing all elements of an array in the same order.

Syntax

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

fun <T> Array<out T>.toList(): List<T>

Parameters

This function does not accepts any parameter.

Return value

This function returns a list containing all elements of an array.

Example 1

Following is a basic example to demonstrate the use of toList() function to return a list −

fun main(args: Array<String>){
   var arr = arrayOf(3, 4, 5, 6)
   print("Array: ")
   println(arr.joinToString())

   // use toList function to convert an array
   val list = arr.toList()
   println("list: "+ list)
}

Output

The above code generate following output −

Array: 3, 4, 5, 6
list: [3, 4, 5, 6]

Example 2

Let's see another example. Here, we use the toList function to return a list containing elements of an array in same order −

fun main() {
   // array of integers
   val intArray = arrayOf(1, 2, 3, 4, 5)
   
   // Convert the array to a list
   val intList: List<Int> = intArray.toList()
   
   // display the list
   println(intList)
}

Output

Following is the output −

[1, 2, 3, 4, 5]

Example 3

The below example converts an array into a list to perform list operations. We then display the student's marks and calculate the average score −

fun main(args: Array<String>) {
   val studentScores = arrayOf(45, 78, 88, 56, 90, 67, 33, 82, 58, 94)
   
   // Convert the array to a list
   val scoreList: List<Int> = studentScores.toList()    
   val passingScore = 60
   
   // Filter the list to get scores of students who passed
   val passingStudents = scoreList.filter { it >= passingScore }    
   println("Students who passed: $passingStudents")
   
   // Calculate the average score of passing students
   val averagePassingScore = if (passingStudents.isNotEmpty()) {
      passingStudents.average()
   } else {
      0.0
   }
   
   println("Average score of passing students: $averagePassingScore")
}

Output

The above code produce following output −

Students who passed: [78, 88, 90, 67, 82, 94]
Average score of passing students: 83.16666666666667