Chaining scope functions in Kotlin - Cheat Sheet & Quick Revision

Recall & Review

beginner

What are Kotlin scope functions?

Kotlin scope functions are special functions like let, run, with, apply, and also that help you execute a block of code within the context of an object, making code more readable and concise.

beginner

What does chaining scope functions mean?

Chaining scope functions means calling one scope function after another on the same object or result, allowing you to perform multiple operations in a clean and readable way.

intermediate

How does the apply function behave in a chain?

apply returns the object it was called on, so you can continue chaining other functions or operations on the original object.

intermediate

What is the difference between let and also when chaining?

let returns the lambda result, while also returns the original object. This affects what the next chained function receives as input.

intermediate

Example: What is the output of this Kotlin code?<br><pre>val result = "hello".let { it.uppercase() }.also { println(it) }</pre>

The code prints HELLO and result holds the string HELLO. This is because let returns HELLO, which is passed to also; also prints it but returns the object it was called on (HELLO).

Which scope function returns the object it was called on, allowing chaining to continue with the original object?

A run

B let

C apply

D with

apply returns the original object, so chaining continues with it.

In chaining, what does let return?

A The lambda result

B The original object

C Unit

D Nothing

let returns the result of the lambda block.

Which scope function is best when you want to perform some operations on an object and return the object itself for further chaining?

A run

B also

C let

D with

also returns the original object after executing the block.

What is the main benefit of chaining scope functions?

A Improving readability and conciseness

B Increasing runtime speed

C Avoiding object creation

D Making code longer

Chaining scope functions makes code easier to read and write.

Given val x = "abc".apply { println(this) }.let { it.length }, what is the value of x?

A "abc"

B null

C Unit

D 3

apply returns the original string, let returns its length, which is 3.

Explain how chaining Kotlin scope functions can improve your code.

Think about how you can do many things with one object in a clean way.

Describe the difference in return values between let and also when used in chaining.

Focus on what each function passes to the next step.