Why lambdas enable functional style in Kotlin - Quick Recap

Recall & Review

beginner

What is a lambda in Kotlin?

A lambda is a small function without a name that can be passed around as a value. It lets you write code blocks that can be used like variables.

beginner

How do lambdas help write functional style code?

Lambdas let you treat functions as data. This means you can pass functions to other functions, return them, and compose them, which is key in functional programming.

beginner

What is a real-life example of using a lambda in Kotlin?

Using a lambda to filter a list: val evens = numbers.filter { it % 2 == 0 } filters even numbers using a lambda that checks if a number is even.

intermediate

Why does functional style prefer lambdas over traditional functions?

Lambdas are concise and can be created inline, making code shorter and easier to read. They also support higher-order functions, which are essential in functional programming.

intermediate

What is a higher-order function and how do lambdas relate to it?

A higher-order function takes functions as parameters or returns them. Lambdas are often used as the functions passed to or returned from these higher-order functions.

What is a lambda in Kotlin?

A An anonymous function that can be passed as a value

B A named function with parameters

C A class that holds data

D A type of variable

A lambda is an anonymous function that can be passed around as a value.

Which feature of lambdas supports functional programming?

A They cannot return values

B They can only be used once

C They must have a name

D They can be passed as arguments to functions

Lambdas can be passed as arguments, enabling higher-order functions, a key part of functional programming.

What does this Kotlin code do? numbers.filter { it > 5 }

A Sorts the numbers

B Filters numbers greater than 5 using a lambda

C Removes all numbers

D Adds 5 to each number

The lambda { it > 5 } filters the list to keep numbers greater than 5.

Why are lambdas preferred in functional style over traditional functions?

A Because they cannot be reused

B Because they require more code

C Because they are concise and can be used inline

D Because they do not support parameters

Lambdas are concise and inline, making functional code cleaner and easier to read.

What is a higher-order function?

A A function that takes or returns other functions

B A function with many parameters

C A function that runs faster

D A function that cannot use lambdas

Higher-order functions take functions as input or return them, often using lambdas.

Explain how lambdas enable functional programming style in Kotlin.

Think about how functions can be treated like data.

Describe a simple example of using a lambda in Kotlin to filter a list.

Focus on how the lambda defines the filtering rule.