Nil coalescing operator (??) in Swift - Mini Project: Build & Apply

Using the Nil Coalescing Operator (??) in Swift

📖 Scenario: You are creating a simple app that shows user profile information. Sometimes, the user might not provide their nickname. You want to display a default nickname when the user does not have one.

🎯 Goal: Build a Swift program that uses the nil coalescing operator ?? to provide a default nickname when the user's nickname is missing.

📋 What You'll Learn

Create an optional String variable called nickname with the value nil.

Create a constant String called defaultNickname with the value "Guest".

Use the nil coalescing operator ?? to create a constant displayName that uses nickname if it has a value, or defaultNickname if nickname is nil.

Print the value of displayName.

💡 Why This Matters

🌍 Real World

Apps often have optional data from users. The nil coalescing operator helps show default values so the app looks friendly and complete.

💼 Career

Understanding optionals and the nil coalescing operator is essential for Swift developers building safe and user-friendly iOS apps.

1

Create the optional nickname variable

Create an optional String variable called nickname and set it to nil.

Swift

# Create an optional String variable called nickname and set it to nil
# Your code here

Need a hint?

Use var nickname: String? = nil to create an optional variable with no value.

2

Create the default nickname constant

Create a constant String called defaultNickname and set it to "Guest".

Swift

var nickname: String? = nil
# Create a constant called defaultNickname with value "Guest"
# Your code here

Need a hint?

Use let defaultNickname = "Guest" to create a constant string.

3

Use the nil coalescing operator to set displayName

Use the nil coalescing operator ?? to create a constant called displayName that uses nickname if it has a value, or defaultNickname if nickname is nil.

Swift

var nickname: String? = nil
let defaultNickname = "Guest"
# Create a constant displayName using nickname ?? defaultNickname
# Your code here

Need a hint?

Use let displayName = nickname ?? defaultNickname to assign the first non-nil value.

4

Print the displayName

Write a print statement to display the value of displayName.

Swift

var nickname: String? = nil
let defaultNickname = "Guest"
let displayName = nickname ?? defaultNickname
# Print displayName
# Your code here

Need a hint?

Use print(displayName) to show the result.