How to use the randomOrNull() method of ArrayList in Kotlin
Overview
The randomOrNull() method is used to return a random element from the ArrayList. If the list is empty, then null is returned.
Syntax
fun <T> Collection<T>.randomOrNull(): T?
Parameter
This method doesn’t take any arguments.
Return value
This method returns a random element from the list if the list is not empty. Otherwise, it returns a null value.
Code example
The code given below demonstrates how we can use the randomOrNull() method:
fun main() {
var list = ArrayList<Int>()
list.add(1)
list.add(2)
list.add(3)
println("The list is $list")
var randElement = list.randomOrNull()
println("Random element from the list ${randElement}")
list = ArrayList<Int>();
println("\nThe list is $list")
randElement = list.randomOrNull()
println("Random element from the list ${randElement}")
}Code explanation
-
Lines 3–6: We create a new ArrayList with the name
listand add three elements to it, using theaddmethod. The list is now[1,2,3]. -
Line 9: We use the
randomOrNullmethod to get a random element from thelist. This method returns a random element from thelist. -
Line 12: We assign an empty
ArrayListas a value to thelistvariable. -
Line 14: We use the
randomOrNullmethod to get a random element from thelist. This method returns anullvalue, because thelistis empty.
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