Optional chaining & error handling basics
Use optional chaining, guard patterns, try?/try!, and do/catch to handle absence and errors. Learn Result as an alternative.
Optional chaining & error handling basics is a free Swift Academy lesson on CoddyKit — lesson 1 of 3. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Swift Academy learning path, one of 3 lessons in the course, and your progress syncs across the web and the CoddyKit app.
Intro
This lesson links Optionals with error handling. Explore chaining, guard patterns, try?/try!, and Result.
Optional chaining
Optional chaining (a?.b?.c) stops and returns nil if any link is nil.
struct User { var address: Address? }
struct Address { var city: String }
let u: User? = User(address: Address(city: "Paris"))
print(u?.address?.city) // Optional("Paris")guard pattern
guard let exits early if an optional is nil, keeping unwrapped value after.
func greet(_ name: String?) {
guard let n = name else {
print("No name")
return
}
print("Hello, \\(n)!")
}
greet(nil)
greet("Ada")try? vs try!
try? returns nil on error. try! crashes if an error is thrown.
enum ParseErr: Error { case bad }
func parse(_ s: String) throws -> Int {
guard let n = Int(s) else { throw ParseErr.bad }
return n
}
let ok = try? parse("10") // Int?
let fail = try? parse("xx") // nil
// let crash = try! parse("xx") // runtime crashdo/catch
do/catch handles thrown errors explicitly.
do {
let n = try parse("42")
print(n)
} catch {
print("error:", error)
}Result type
Result<T,Error> encodes success/failure without throwing.
func safeParse(_ s: String) -> Result<Int,Error> {
do { return .success(try parse(s)) }
catch { return .failure(error) }
}
print(safeParse("5"))
print(safeParse("oops"))Optional chaining Q
Quick check: What does optional chaining do?
Recap
Recap: Combine optionals and error handling. Use chaining, guard, try?/try!, do/catch, and Result to manage absence and failures safely.
Frequently asked questions
Is the “Optional chaining & error handling basics” lesson free?
Yes — the full text of “Optional chaining & error handling basics” is free to read here on the web, and the Swift Academy course includes 3 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Swift Academy course, upgrade to CoddyKit PRO.
What will I learn in “Optional chaining & error handling basics”?
Use optional chaining, guard patterns, try?/try!, and do/catch to handle absence and errors. Learn Result as an alternative. You practise Swift Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Swift Academy?
No prior experience is required. Swift Academy on CoddyKit is structured for beginners through advanced learners; this is — lesson 1 of 3, so you can start here or from the beginning and move at your own pace.
How long does the “Optional chaining & error handling basics” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Swift Academy lesson?
Yes. Every Swift Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Optional chaining & error handling basics
- do/catch & defining errors (enums)
- Result types — Result