How to use the elementAtOrElse method of HashSet in Kotlin
Overview
The elementAtOrElse() method of HashSet returns the element at the given index. If the index is greater than the length of the set then the defaultValue function is invoked and the value returned from the function is returned.
Syntax
fun <T> Iterable<T>.elementAtOrElse(
index: Int,
defaultValue: (Int) -> T
): T
Parameters
This method takes two parameters:
-
index: This is the index of the element to be returned. -
defaultValue: This is a function that will be invoked when the index is greater than the length ofset.
Return value
This method returns the element at the given index.
Code
The code below demonstrates how to use the elementAtOrElse() method:
fun main() {
//create a new HashSet which can have String type as elements
var set = hashSetOf<String>()
// add two entries
set.add("1")
set.add("2")
println("\nThe set is : $set")
// get element at index 1
var ele = set.elementAtOrElse(1) {"default value"}
println("\nset.elementAt(2) : $ele")
// get element at index 3
ele = set.elementAtOrElse(3) {"default value"}
println("\nset.elementAt(3) : $ele")
}Explanation
-
Line 3: We create a new
HashSetobject with the nameset. We use thehashSetOf()method to create an emptyHashSet. -
Lines 6 to 7: We add two new elements,
(1,2), to thesetusing theadd()method. -
Line 12: We use the
elementAtOrElsemethod with a1as an argument. TheelementAtOrElsechecks for the element at index1. In ourset, the element2is present in index1, so it is returned. -
Line 16: We use the
elementAtOrElsemethod with a3as an argument. TheelementAtOrElsechecks for the element at index3. In ourset, there is no element present in index3, so thedefaultValuefunction is invoked. ThedefaultValuefunction returnsdefault valueas result.
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