When to use sequences in Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a sequence from a list.

Kotlin

val numbers = listOf(1, 2, 3, 4, 5)
val seq = numbers.[1]()

Drag options to blanks, or click blank then click option'

AtoList

BasSequence

Cmap

Dfilter

Attempts:

3 left

💡 Hint

Common Mistakes

Using toList() instead of asSequence().

Use asSequence() to convert a list to a sequence for lazy operations.

2fill in blank

medium

Complete the code to lazily filter even numbers using sequences.

Kotlin

val seq = sequenceOf(1, 2, 3, 4, 5)
val evens = seq.[1] { it % 2 == 0 }

Drag options to blanks, or click blank then click option'

Afilter

Bmap

Creduce

Dfold

Attempts:

3 left

💡 Hint

Common Mistakes

Using map which transforms elements instead of filtering.

Use filter to select elements matching a condition lazily in sequences.

3fill in blank

hard

Fix the error in the code to convert a list to a sequence and map values.

Kotlin

val list = listOf(1, 2, 3)
val result = list.[1]().map { it * 2 }.toList()

Drag options to blanks, or click blank then click option'

AasSequence

BtoList

CsequenceOf

Dfilter

Attempts:

3 left

💡 Hint

Common Mistakes

Using toList() which returns the same list, not a sequence.

asSequence() converts the list to a sequence for lazy mapping before converting back to a list.

4fill in blank

hard

Fill both blanks to create a sequence from a list and lazily map values.

Kotlin

val list = listOf(1, 2, 3, 4)
val seq = list.[1]().[2] { it + 1 }

Drag options to blanks, or click blank then click option'

AasSequence

Bfilter

Cmap

DtoList

Attempts:

3 left

💡 Hint

Common Mistakes

Using toList() before map which is eager, not lazy.

First convert the list to a sequence with asSequence(), then lazily transform elements with map.

5fill in blank

hard

Fill all three blanks to create a sequence, filter even numbers, and convert to list.

Kotlin

val numbers = listOf(1, 2, 3, 4, 5)
val evens = numbers.[1]().[2] { it % 2 == 0 }.[3]()

Drag options to blanks, or click blank then click option'

AasSequence

Bfilter

CtoList

Dmap

Attempts:

3 left

💡 Hint

Common Mistakes

Using map instead of filter to select even numbers.

Convert list to sequence with asSequence(), lazily filter evens with filter, then convert back to list with toList().