Set algebra (union, intersection, difference) in Swift - Mini Project: Build & Apply

Set algebra (union, intersection, difference)

📖 Scenario: You are organizing two groups of friends who like different sports. You want to find out who likes either sport, who likes both, and who likes only one of the sports.

🎯 Goal: Build a Swift program that uses sets to find the union, intersection, and difference of two groups of friends.

📋 What You'll Learn

Create two sets of strings representing friends who like basketball and soccer.

Create a variable to hold the union of both sets.

Create a variable to hold the intersection of both sets.

Create a variable to hold the difference of basketball friends who do not like soccer.

Print the results clearly.

💡 Why This Matters

🌍 Real World

Sets help manage groups of items or people, like customers, tags, or preferences, without duplicates.

💼 Career

Understanding set operations is useful in data processing, filtering, and combining information efficiently in software development.

1

Create two sets of friends

Create two sets called basketballFans and soccerFans with these exact values: basketballFans contains "Alice", "Bob", "Charlie" and soccerFans contains "Bob", "Diana", "Eve".

Swift

// Create the sets basketballFans and soccerFans with the exact names and values
// Your code here

Need a hint?

Use let to create sets with square brackets and commas separating names.

2

Create variables for union, intersection, and difference

Create three variables called allFans, bothFans, and onlyBasketballFans. Set allFans to the union of basketballFans and soccerFans. Set bothFans to the intersection of basketballFans and soccerFans. Set onlyBasketballFans to the difference of basketballFans minus soccerFans.

Swift

let basketballFans: Set = ["Alice", "Bob", "Charlie"]
let soccerFans: Set = ["Bob", "Diana", "Eve"]
// Create allFans as union of basketballFans and soccerFans
// Create bothFans as intersection of basketballFans and soccerFans
// Create onlyBasketballFans as difference of basketballFans minus soccerFans
// Your code here

Need a hint?

Use .union(), .intersection(), and .subtracting() methods on sets.

3

Print the results

Write three print statements to display the contents of allFans, bothFans, and onlyBasketballFans with clear labels.

Swift

let basketballFans: Set = ["Alice", "Bob", "Charlie"]
let soccerFans: Set = ["Bob", "Diana", "Eve"]

let allFans = basketballFans.union(soccerFans)
let bothFans = basketballFans.intersection(soccerFans)
let onlyBasketballFans = basketballFans.subtracting(soccerFans)

// Print allFans with label "All fans:"
// Print bothFans with label "Fans of both sports:"
// Print onlyBasketballFans with label "Only basketball fans:"
// Your code here

Need a hint?

Use print with string interpolation and .sorted() to show sets in order.

4

Run the program and see the output

Run the program to display the sets of fans with their labels exactly as printed by the print statements.

Swift

let basketballFans: Set = ["Alice", "Bob", "Charlie"]
let soccerFans: Set = ["Bob", "Diana", "Eve"]

let allFans = basketballFans.union(soccerFans)
let bothFans = basketballFans.intersection(soccerFans)
let onlyBasketballFans = basketballFans.subtracting(soccerFans)

print("All fans: \(allFans.sorted())")
print("Fans of both sports: \(bothFans.sorted())")
print("Only basketball fans: \(onlyBasketballFans.sorted())")

// Run the program and check the output

Need a hint?

Check the console output matches exactly the printed lines with sorted arrays.