20 Useful Tricks and Techniques in Kotlin

Kotlin is a modern programming language that has quickly gained popularity among developers. It is known for its concise syntax, powerful features, and full interoperability with Java. In this blog post, we will explore 20 useful tricks and techniques that can help you write cleaner, more efficient code in Kotlin. From using the Elvis operator to safely access nested properties to using the filter function to filter a list of objects, these tricks and techniques will help you make the most of the language. Whether you’re a beginner or an experienced developer, this post will provide valuable insights into how to write better Kotlin code. So let’s dive in and start learning!

1. Using the “it” keyword to reference the current element in a lambda expression:

val numbers = listOf(1, 2, 3, 4, 5)
val doubledNumbers = numbers.map { it * 2 }

2. Using the “apply” function to initialize an object and set properties in a single line:

val person = Person().apply {
    firstName = "John"
    lastName = "Doe"
    age = 30
}

3. Using the “let” function to perform operations on a nullable variable only if it is not null:

val name: String? = "John"
name?.let { println("My name is $it") }

4. Using the “with” function to perform operations on a specific object without having to repeat its name:

val person = Person(firstName = "John", lastName = "Doe", age = 30)
with(person) {
    println("My name is $firstName $lastName")
    println("I am $age years old")
}

5. Using the “also” function to perform operations on an object after it has been initialized:

val person = Person().also {
    it.firstName = "John"
    it.lastName = "Doe"
    it.age = 30
}

6. Using the “takeIf” function to return an object if a certain condition is met:

val name: String? = "John"
val validName = name.takeIf { it.length >= 3 }

7. Using the “takeUnless” function to return an object if a certain condition is not met:

val name: String? = "John"
val validName = name.takeUnless { it.length < 3 }

8. Using the “run” function to perform operations on an object and return a result:

val person = Person(firstName = "John", lastName = "Doe", age = 30)
val fullName = person.run { "$firstName $lastName" }

9. Using the “withIndex” function to iterate through a collection and access both the element and its index:

val numbers = listOf(1, 2, 3, 4, 5)
for ((index, number) in numbers.withIndex()) {
    println("$index: $number")
}

10. Using the “groupBy” function to group elements in a collection by a certain key:

val people = listOf(
    Person(firstName = "John", lastName = "Doe", age = 30),
    Person(firstName = "Jane", lastName = "Doe", age = 25),
    Person(firstName = "Bob", lastName = "Smith", age = 35)
)
val peopleByLastName = people.groupBy { it.lastName }

11. Using destructuring declarations to extract values from a data class:

data class Person(val firstName: String, val lastName: String, val age: Int)
val person = Person("John", "Doe", 30)
val (firstName, lastName, age) = person

12. Using the “ifNotNull” function to perform operations on a nullable variable only if it is not null:

val name: String? = "John"
name?.ifNotNull { println("My name is $it") }

13. Using the “withDefault” function to provide a default value for a nullable variable:

val name: String? = null
val defaultName = name.withDefault { "John" }

14. Using the “orElse” function to provide a default value for a nullable variable:

val name: String? = null
val defaultName = name.orElse { "John" }

15. Using the “orElseGet” function to provide a default value for a nullable variable:

val name: String? = null
val defaultName = name.orElseGet { "John" }

16. Using the “orElseThrow” function to throw an exception for a nullable variable:

val name: String? = null
val defaultName = name.orElseThrow { IllegalArgumentException("Name is required") }

17. Using the “orNull” function to provide a null value for a nullable variable:

Using the "orNull" function to provide a null value for a nullable variable:

18. Using the “or” function to provide a default value for a nullable variable:

val name: String? = null
val defaultName = name.or { "John" }

19. Using the “let” function to perform operations on a nullable variable only if it is not null:

20. Using the “let” function to perform operations on a nullable variable only if it is not null and return a result:

val name: String? = "John"
val upperName = name?.let { it.toUpperCase() }