Kotlin program to convert an array to a Set (HashSet)

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In this program, you will learn how to convert an array to a collection in Kotlin.

Example1Convert an array to a collection

import java.util.*
fun main(args: Array<String>) {
　　　　val array = arrayOf("a", "b", "c")
　　　　val set = HashSet(Arrays.asList(*array))
　　　　println("Set: $set")
}

When running the program, the output is:

Set: [a, b, c]

In the above program, we have an array named array. To convert an array to a set, we first convert it to a list using asList() because HashSet accepts a list as a constructor.

Then, we initialize the set with the elements of the converted list.

Example2Convert the set collection to an array

import java.util.*
fun main(args: Array<String>) {
　　　　val set = HashSet<String>()
　　　　set.add("a")
　　　　set.add("b")
　　　　set.add("c")
　　　　val array = arrayOfNulls<String>(set.size)
　　　　set.toArray(array)
　　　　println("Array: [${Arrays.toString(array)}]")
}

When running the program, the output is:

Array: [a, b, c]

In the above program, we have a HashSet named set. To convert a set to an array, we first create an array of length equal to the size of the collection and use the toArray() method.

The equivalent Java code is as follows:Java Program to Interconvert Array and Set.

Comprehensive Collection of Kotlin Examples