Sorted and custom comparators in Swift - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to sort the array in ascending order.

Swift

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

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Amap

Bsorted

Creversed

Dsort

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'sort()' which sorts the array in place and returns void.

Using 'reversed()' which reverses the array order.

Using 'map()' which transforms elements but does not sort.

The 'sorted()' method returns a new array sorted in ascending order.

2fill in blank

medium

Complete the code to sort the array in descending order using a closure.

Swift

let numbers = [5, 3, 8, 1]
let sortedNumbers = numbers.sorted(by: { $0 [1] $1 })

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A>

B<

C==

D<=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' which sorts ascending.

Using '==' which does not sort properly.

Using '<=' which sorts ascending with duplicates.

Using '>' in the closure sorts the array in descending order.

3fill in blank

hard

Fix the error in the code to sort an array of strings by their length.

Swift

let words = ["apple", "banana", "fig", "date"]
let sortedWords = words.sorted(by: { $0.[1] < $1.count })

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Asize

Blength()

Ccount

Dlength

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'length' which is not a Swift String property.

Using 'size' which does not exist for strings.

Using 'length()' which is not a valid method.

Strings in Swift use 'count' property to get their length.

4fill in blank

hard

Fill both blanks to create a dictionary of words and their lengths, including only words longer than 4 characters.

Swift

let words = ["apple", "banana", "fig", "date"]
let wordLengths = Dictionary(uniqueKeysWithValues: words.filter { $0.count [2] 4 }.map { word in (word, [1]) })

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Aword.count

Bcount

C>

Dlength

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'count' alone without 'word.' prefix.

Using '<' instead of '>' for filtering.

Using 'length' which is not a Swift property.

Use 'word.count' to get length and '>' to filter words longer than 4.

5fill in blank

hard

Fill all three blanks to create a sorted array of tuples (word, length) for words with length at least 5, sorted by length descending.

Swift

let words = ["apple", "banana", "fig", "date"]
let filteredSorted = words.filter { $0.count [1] 5 }.map { [2] in ([2], [2].count) }.sorted { $0.1 [3] $1.1 }

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A>=

Bword

Cw

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' instead of '>=' for filtering.

Using 'word' instead of 'w' for the map variable.

Using '<' in sorted closure which sorts ascending.

Filter words with length >= 5, map to tuples (w, w.count), and sort descending by length using '>' operator.