It keyword for single parameter in Kotlin - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the it keyword represent in Kotlin lambdas with a single parameter?

In Kotlin, it is an implicit name for the single parameter in a lambda expression when the parameter name is not explicitly specified.

beginner

How do you use it in a Kotlin lambda to print each element of a list?

You can write list.forEach { println(it) }. Here, it refers to each element of the list during iteration.

intermediate

Can you use it if your lambda has more than one parameter?

No. The it keyword is only available when the lambda has exactly one parameter. For multiple parameters, you must name them explicitly.

beginner

Rewrite this lambda using it: list.map { number -> number * 2 }

Using it, it becomes list.map { it * 2 }. This works because the lambda has a single parameter.

beginner

Why is using it helpful in Kotlin lambdas?

Using it makes the code shorter and cleaner when the lambda has only one parameter, improving readability.

In Kotlin, when can you use the it keyword inside a lambda?

A When the lambda has no parameters

B When the lambda has exactly one parameter

C When the lambda has multiple parameters

D Only in functions, not lambdas

it is the implicit name for the single parameter in a lambda with exactly one parameter.

What does it represent in this code: list.forEach { println(it) }?

A The current element of the list

B The index of the element

C The entire list

D A Boolean value

it refers to each element of the list as the lambda runs for each item.

Which of these is a correct use of it in Kotlin?

A list.map { it * 2 }

B list.map { a, b -> it + b }

C list.filter { }

D list.forEach { println() }

it can only be used when the lambda has one parameter, like in list.map { it * 2 }.

If a lambda has two parameters, how do you refer to them?

A Use <code>it</code> for the first and <code>that</code> for the second

B You cannot use lambdas with two parameters

C Use <code>it</code> for both

D You must name both parameters explicitly

When there are multiple parameters, you must name them explicitly in the lambda.

What is the benefit of using it in Kotlin lambdas?

A Improves performance

B Allows lambdas to have multiple parameters

C Makes code shorter and easier to read for single-parameter lambdas

D Automatically types the parameter

it helps keep code concise and clean when the lambda has one parameter.

Explain how the it keyword works in Kotlin lambdas and when you can use it.

Think about how Kotlin lets you skip naming the parameter when there is only one.

Give an example of a Kotlin lambda using it and explain what it refers to in your example.

Try a simple list operation like forEach or map.