Sorted and sortedBy in Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to sort the list in ascending order.

Kotlin

val numbers = listOf(5, 3, 8, 1)
val sortedNumbers = numbers.[1]()

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

AorderBy

Bsort

Csorted

Darrange

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'sort' which is not a function on immutable lists.

Using 'orderBy' or 'arrange' which are not Kotlin functions.

The sorted() function returns a new list with elements sorted in ascending order.

2fill in blank

medium

Complete the code to sort the list of strings by their length.

Kotlin

val words = listOf("apple", "banana", "kiwi", "pear")
val sortedWords = words.[1] { it.length }

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AsortedBy

Bsorted

CsortBy

DorderBy

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'sorted' which sorts by natural order, not by length.

Using 'sortBy' which is a mutable list function.

The sortedBy function sorts elements according to the value returned by the selector function, here it.length.

3fill in blank

hard

Fix the error in the code to sort the list of pairs by the second value.

Kotlin

val pairs = listOf(Pair("a", 3), Pair("b", 1), Pair("c", 2))
val sortedPairs = pairs.[1] { it.second }

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Asort

BsortedBy

Csorted

DsortBy

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'sortBy' on an immutable list causes an error.

Using 'sorted' without a selector sorts by natural order.

sortedBy returns a new sorted list by the selector. sortBy works only on mutable lists.

4fill in blank

hard

Fill both blanks to create a map of words to their lengths, including only words longer than 3 characters.

Kotlin

val words = listOf("cat", "elephant", "dog", "horse")
val wordLengths = { [1] : [2] for word in words if word.length > 3 }

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Aword

Blen(word)

Cword.length

Dword.size

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'len(word)' which is Python syntax, not Kotlin.

Using 'word.size' which is not a property of String in Kotlin.

The map keys are the words themselves, and the values are their lengths using word.length.

5fill in blank

hard

Fill all three blanks to create a map of uppercase words to their lengths, including only words longer than 4 characters.

Kotlin

val words = listOf("apple", "bat", "carrot", "dog")
val result = { [1] : [2] for word in words if word.[3] 4 }

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Aword.uppercase()

Bword.length

Clength

Dlength()

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'length()' which is not a Kotlin property but a method in some languages.

Using 'word.length()' which is invalid in Kotlin.

The key is the uppercase word using word.uppercase(), the value is the length with word.length, and the condition checks word.length > 4.