Lambda function in Kotlin. Example 1: var myFunc1 : (a:Int, b:Int) -> Int = { p1, p2 -> p1 + p2 };

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Lambda function in Kotlin. Example 1: var myFunc1 : (a:Int, b:Int) -> Int = { p1, p2 -> p1 + p2 };

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Lambda function in Kotlin

last updated: 2 May 2024

Lambda function denoted by ->
Lambda function is a shortened version of the unnamed function.

The Lambda function is described as follows:

Example 1. no input parameters, returns nothing

Lambda Declaration

// no input parameters, returns nothing
// Unit is an empty type
() -> Unit

Lambda Body

// function displays Hello
{ -> println("Hello") }

Full example:

Kotlin

// Create the variable myFunc1: this is a function with no input parameters, returns nothing
var myFunc1 : () -> Unit;

// For variable myFunc1 set body of the function
myFunc1 = { -> println("Hello") };

// call the lambda function
myFunc1();
// We'll see on the screen Hello

Example 2. No input parameters, returns Int

Lambda Declaration

// no input parameters, returns Int
() -> Int

Lambda Body

// function only returns 30
{ -> 30 }

Full example:

Kotlin

// Create a variable myFunc1: this is a function with no input parameters, returns Int
var myFunc1 : () -> Int;

// For variable myFunc1 set body of the function
myFunc1 = { -> 30 };

// call the lambda function
var result = myFunc1();
// result = 30

Example 3. With 2 input parameters, returns Int

Lambda Declaration

// with 2 input parameters, returns Int
(a:Int, b:Int) -> Int

Lambda Body

// function calculate sum of 2 input parameters and return sum
{ p1, p2 -> p1 + p2 }

Full example:

Kotlin

// Create a variable myFunc1: this is a function with 2 input parameters, returns Int
var myFunc1 : (a:Int, b:Int) -> Int;

// For variable myFunc1 set body of the function
myFunc1 = { p1, p2 -> p1 + p2 };

// call the lambda function
var result = myFunc1(5, 21);
// result = 26

Writing a program

Step 1. Creating a new project

Create a new simple console project on Kotlin in IntelliJ IDEA ...

Step 2. Let's change the code in the file Main.kt

Kotlin

fun main()
{
     var myFunc1 : (a:Int, b:Int) -> Int;

     myFunc1 = { p1, p2 -> p1 + p2 };

     var result = myFunc1(5, 21);
     println(result)
}

Step 3. Launching the project

See the result 26 at the bottom of the screen