Question

How to write custom callback function to an array (apply a function to each element) in Kotlin

Answer 1

// Custom callback function 
 
// Custom function that applies a callback to each element
fun applyToArray(arr: Array<Int>, callback: (Int) -> Int): Array<Int> {
    val result = Array(arr.size) { 0 }
    for (i in arr.indices) {
        result[i] = callback(arr[i])   // apply the callback
    }
    return result
}

// callback function 
fun square(x: Int): Int = x * x

fun main() {
    val numbers = arrayOf(2, 4, 6, 8)

    val squared = applyToArray(numbers, ::square)

    println(squared.toList())   
}

 
/*
run:
 
[4, 16, 36, 64]
 
*/
 

 

70+ SQL courses for beginners and professionals