Set algebra (union, intersection, difference) in Swift - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to find the union of two sets.

Swift

let setA: Set<Int> = [1, 2, 3]
let setB: Set<Int> = [3, 4, 5]
let unionSet = setA.[1](setB)
print(unionSet.sorted())

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

Aunion

B-

Cintersect

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+' operator which is not defined for sets in Swift.

Using 'intersect' which finds common elements.

The union method returns a new set with all elements from both sets.

2fill in blank

medium

Complete the code to find the intersection of two sets.

Swift

let setX: Set<String> = ["apple", "banana", "cherry"]
let setY: Set<String> = ["banana", "date", "fig"]
let commonFruits = setX.[1](setY)
print(commonFruits.sorted())

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Aintersect

Bunion

Cintersection

Dsubtract

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'union' which combines all elements.

Using 'subtract' which removes elements.

The intersection method returns a new set with elements common to both sets.

3fill in blank

hard

Fix the error in the code to find the difference between two sets.

Swift

let set1: Set<Int> = [10, 20, 30, 40]
let set2: Set<Int> = [30, 40, 50]
let diffSet = set1.[1](set2)
print(diffSet.sorted())

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Asubtract

Bdifference

Csubtracting

Ddiff

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'subtract' which is a mutating method, not returning a new set.

Using incorrect method names like 'diff'.

The correct method to find elements in set1 not in set2 is subtracting.

4fill in blank

hard

Fill both blanks to create a set of fruits that are in setA but not in setB.

Swift

let setA: Set<String> = ["orange", "apple", "banana"]
let setB: Set<String> = ["banana", "kiwi"]
let result = setA.[1](setB)
print(result.[2]())

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Asubtracting

Bsorted

Cdifference

DsortedDescending

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'difference' which is not a valid method.

Using 'sortedDescending' which sorts in reverse order.

subtracting returns elements in setA not in setB. sorted() sorts the result in ascending order.

5fill in blank

hard

Fill all three blanks to create a dictionary with fruit names as keys (uppercase) and their counts as values, only for fruits with count greater than 1.

Swift

let fruits = ["apple", "banana", "apple", "cherry", "banana", "banana"]
let counts = Dictionary(grouping: fruits, by: [1]).mapValues { $0.count }
let filtered = counts.filter { $0.value [2] 1 }
let result = filtered.mapKeys { [3] }
print(result)

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A{ $0 }

B>

C{ $0.uppercased() }

D{ $0.lowercased() }

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong grouping key.

Using wrong comparison operator.

Not converting keys to uppercase.

Grouping by the fruit name itself ({ $0 }), filtering counts greater than 1, and mapping keys to uppercase ({ $0.uppercased() }) creates the desired dictionary.