Kotlin Kotlin Functions and Lambdas 2

Question 1

What is the type of a lambda that takes an Int and returns a String in Kotlin?

Accepted Answer

(Int) -> String

Answer

Lambda<Int, String>

Answer

Function<Int, String>

Answer

Int => String

Question 2

What does the `crossinline` modifier do on a lambda parameter?

Accepted Answer

Prevents non-local returns inside the lambda

Answer

Prevents the lambda from being inlined

Answer

Forces the lambda to run on a separate thread

Answer

Makes the lambda nullable

Question 3

How do you reference an existing function as a value in Kotlin?

Accepted Answer

Using the `::` operator

Answer

Using the `ref` keyword

Answer

Using the `&` operator

Answer

Wrapping it in a lambda explicitly

Question 4

Which built-in higher-order function applies a transformation to each element of a collection?

Accepted Answer

map

Answer

filter

Answer

reduce

Answer

fold

Question 5

What does `noinline` do on an inline function parameter?

Accepted Answer

Prevents that specific lambda parameter from being inlined

Answer

Forces the lambda to be inlined

Answer

Makes the lambda run asynchronously

Answer

Marks the parameter as optional

Question 6

What is the difference between `fun` and a lambda in Kotlin?

Accepted Answer

`fun` requires explicit return, lambdas return the last expression

Answer

Lambdas cannot have return types

Answer

Lambdas cannot capture outer variables

Answer

`fun` is always anonymous, lambdas always have names