Best Kotlin Programming Books to Buy in February 2026
Kotlin in Action, Second Edition
How to Build Android Applications with Kotlin: A hands-on guide to developing, testing, and publishing production-grade Android 16 apps
Kotlin from Scratch: A Project-Based Introduction for the Intrepid Programmer
Head First Kotlin: A Brain-Friendly Guide
Programming Android with Kotlin: Achieving Structured Concurrency with Coroutines
Functional Programming in Kotlin
Kotlin Design Patterns and Best Practices: Elevate your Kotlin skills with classical and modern design patterns, coroutines, and microservices
The largest array/collection in Kotlin is probably the ArrayList class, which is a resizable implementation of the List interface. This class allows for dynamic resizing of the collection, making it suitable for scenarios where the size of the collection may grow or shrink during runtime. ArrayLists are commonly used in Kotlin for storing and manipulating large amounts of data efficiently.
What is the use of collections.emptyList() function in Kotlin?
The emptyList() function in Kotlin is used to create an immutable empty list. It returns an instance of the List interface that is guaranteed to be empty and immutable, meaning that you cannot add or remove elements from it.
This function is useful when you need to work with an empty list but do not want to create a new instance every time. By using emptyList(), you can reuse the same instance whenever an empty list is needed, which can help improve performance and reduce memory usage in your application.
How to sort elements in a collection in Kotlin?
To sort elements in a collection in Kotlin, you can use the sorted() function. Here's an example:
val numbers = listOf(5, 2, 10, 1, 8) val sortedNumbers = numbers.sorted()
println(sortedNumbers) // Output: [1, 2, 5, 8, 10]
You can also sort elements in descending order using the sortedDescending() function:
val numbers = listOf(5, 2, 10, 1, 8) val sortedNumbersDescending = numbers.sortedDescending()
println(sortedNumbersDescending) // Output: [10, 8, 5, 2, 1]
If you have a mutable collection and want to sort it in place, you can use the sort() function:
val mutableNumbers = mutableListOf(5, 2, 10, 1, 8) mutableNumbers.sort()
println(mutableNumbers) // Output: [1, 2, 5, 8, 10]
You can also provide a custom comparator to the sortedWith() function if you need a custom sorting order for your elements:
val words = listOf("apple", "banana", "orange", "cherry") val sortedWords = words.sortedWith(compareBy { it.length })
println(sortedWords) // Output: [apple, cherry, banana, orange]
These are some ways you can sort elements in a collection in Kotlin.
How to initialize an empty array in Kotlin?
To initialize an empty array in Kotlin, you can use the arrayOf() function with no arguments. This will create a new empty array of the specified type. For example:
val myArray = arrayOf()
This will create an empty array of type String. You can also specify a different type for the array by changing the type parameter within the angle brackets.