Tuples for grouped values in Swift - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this tuple unpacking?

Consider the following Swift code that uses a tuple to group values and then unpacks them. What will be printed?

Swift

let person = (name: "Alice", age: 30, city: "Paris")
let (name, age, city) = person
print("\(name) is \(age) years old and lives in \(city).")

A name is 30 years old and lives in city.

B Alice is 30 years old and lives in Paris.

C (name, age, city)

D 30 is Alice years old and lives in Paris.

💡 Hint

Look at how the tuple is unpacked into variables and used in the print statement.

The tuple 'person' has named elements. Unpacking assigns each element to variables 'name', 'age', and 'city'. The print statement uses these variables to form the output string.

🧠 Conceptual

intermediate

Which tuple declaration is correct in Swift?

You want to create a tuple that groups a person's name as a String and age as an Int. Which of the following declarations is correct?

A let person = (name: "Bob", age: "25")

B let person = ("Bob", "25")

C let person: (String, Int) = ("Bob", 25)

D let person: (name: String, age: Int) = ("Bob", "25")

💡 Hint

Check the types of each element in the tuple and their matching values.

Option C correctly declares a tuple with types (String, Int) and assigns matching values. Option C has age as a String instead of Int. Option C uses Strings for both elements without type annotation. Option C mismatches types by assigning a String to age which expects Int.

🔧 Debug

advanced

Why does this tuple code cause a compile error?

Examine the Swift code below. Why does it cause a compile-time error?

Swift

let coordinates = (x: 10, y: 20)
let (a, b, c) = coordinates
print(a, b, c)

A The tuple elements must be accessed only by name, not by unpacking.

B The tuple elements are named, so you cannot unpack them into variables.

C You cannot print multiple variables separated by commas in Swift.

D The tuple 'coordinates' has only two elements, but three variables are used to unpack it.

💡 Hint

Count the number of elements in the tuple and the number of variables used to unpack.

The tuple 'coordinates' has two elements (x and y). Trying to unpack into three variables (a, b, c) causes a compile error because the counts do not match.

📝 Syntax

advanced

Which option correctly creates a tuple with mixed types?

You want to create a tuple with a String, an Int, and a Bool in Swift. Which of the following is syntactically correct?

A let info = ("John", 42, true)

B let info = ("John"; 42; true)

C let info = ["John", 42, true]

D let info = {"John", 42, true}

💡 Hint

Remember the syntax for tuples uses parentheses and commas.

Option A uses parentheses and commas, which is the correct syntax for tuples. Option A uses semicolons which is invalid. Option A uses square brackets which create arrays, not tuples. Option A uses curly braces which is invalid syntax here.

🚀 Application

expert

What is the value of 'result' after this tuple swap?

Given the following Swift code that swaps two values using tuples, what is the value of 'result' after execution?

Swift

var a = 5
var b = 10
(a, b) = (b, a)
let result = (a, b)

A (10, 5)

B (5, 10)

C (0, 0)

D (a, b)

💡 Hint

Look at how the tuple assignment swaps the values of 'a' and 'b'.

The tuple assignment swaps the values of 'a' and 'b'. Initially a=5 and b=10, after swap a=10 and b=5. So 'result' is (10, 5).