Kotlin Array.flatten()

Kotlin Array.flatten() Tutorial

In Kotlin, the `Array.flatten()` function is used to flatten an array of arrays into a list. It simplifies the process of converting nested arrays into a flat list of elements.

This tutorial will explore the syntax of the `Array.flatten()` function and provide examples of its usage in Kotlin arrays.

Syntax

The syntax of the `Array.flatten()` function is as follows:

``fun <T> Array<out T>.flatten(): List<T>``

The `flatten()` function returns a List.

Examples for Array.flatten() function

1. Flattening a 2D Array

In this example, we’ll use the `flatten()` function to flatten a 2D array into a single list of elements.

Kotlin Program

``````fun main() {
val twoDArray = arrayOf(arrayOf(1, 2, 3), arrayOf(4, 5, 6), arrayOf(7, 8, 9))

// Using flatten() to flatten the 2D array
val flatList = twoDArray.flatten()

// Printing the original 2D array and the flattened list
println("2D Array:\n[\${twoDArray.map { it.contentToString() }.joinToString("\n")}]\n")
println("Flattened List:\n\$flatList")
}``````

Output

``````2D Array:
[[1, 2, 3]
[4, 5, 6]
[7, 8, 9]]

Flattened List:
[1, 2, 3, 4, 5, 6, 7, 8, 9]``````

Summary

In this tutorial, we’ve covered the `flatten()` function in Kotlin arrays, its syntax, and how to use it to convert an array of arrays into a list. This function is particularly useful when working with nested arrays, providing a concise way to flatten the structure and access individual elements.