Set creation and operations in Swift - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Swift code using sets?

Consider the following Swift code that creates and manipulates sets. What will be printed?

Swift

let setA: Set<Int> = [1, 2, 3, 4]
let setB: Set<Int> = [3, 4, 5, 6]
let unionSet = setA.union(setB)
print(unionSet.sorted())

A [3, 4]

B [1, 2]

C [1, 2, 3, 4, 5, 6]

D [5, 6]

💡 Hint

Think about what the union operation does to two sets.

The union of two sets combines all unique elements from both sets. Here, setA and setB combined have elements 1, 2, 3, 4, 5, and 6. Sorting them gives [1, 2, 3, 4, 5, 6].

❓ Predict Output

intermediate

What does this Swift code print after set intersection?

Look at this Swift code that finds the intersection of two sets. What is the output?

Swift

let setX: Set<Int> = [10, 20, 30, 40]
let setY: Set<Int> = [30, 40, 50, 60]
let intersectionSet = setX.intersection(setY)
print(intersectionSet.sorted())

A [10, 20]

B []

C [50, 60]

D [30, 40]

💡 Hint

Intersection returns only elements common to both sets.

The intersection of setX and setY contains elements present in both sets, which are 30 and 40. Sorting them results in [30, 40].

❓ Predict Output

advanced

What is the output of this Swift code using symmetricDifference?

This Swift code uses symmetricDifference on two sets. What will be printed?

Swift

let set1: Set<Int> = [1, 2, 3, 4, 5]
let set2: Set<Int> = [4, 5, 6, 7]
let symDiff = set1.symmetricDifference(set2)
print(symDiff.sorted())

A [1, 2, 3, 6, 7]

B [4, 5]

C [1, 2, 3, 4, 5, 6, 7]

D [6, 7]

💡 Hint

Symmetric difference returns elements in either set but not in both.

The symmetric difference excludes elements common to both sets (4 and 5). So the result is [1, 2, 3, 6, 7].

❓ Predict Output

advanced

What is the count of elements after subtracting sets in Swift?

Given these two sets, what is the count of elements in the result after subtracting setB from setA?

Swift

let setA: Set<Int> = [100, 200, 300, 400, 500]
let setB: Set<Int> = [300, 400, 600]
let differenceSet = setA.subtracting(setB)
print(differenceSet.count)

A 2

B 3

C 4

D 5

💡 Hint

Subtracting removes elements of setB from setA.

Elements 300 and 400 are removed from setA. Remaining elements are 100, 200, and 500, so count is 3.

🧠 Conceptual

expert

Which Swift set operation produces this output?

You have two sets: setM = [2, 4, 6, 8] and setN = [1, 2, 3, 4]. Which operation on setM and setN produces the output [1, 3, 6, 8] when sorted?

A setM.union(setN).subtracting(setM.intersection(setN))

B setM.symmetricDifference(setN)

C setM.intersection(setN).union(setM.subtracting(setN))

D setM.subtracting(setN).union(setN.subtracting(setM))

💡 Hint

Think about how union, intersection, and subtracting combine to form symmetric difference.

Option A computes union minus intersection, which is the symmetric difference. The output is [1, 3, 6, 8].