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Test Your Knowledge: Swift - Optional Chaining

Tags: optional chaining, optionals

Summary

Test on optional chaining to safely return a nil or non-nil value from a series of optionals chained together.

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Swift - Optional Chaining

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Swift - Optional Chaining

Review Answers for Questions in this Test

1. var display = customer.address!.line2! - address and line2 are optionals. What might be the problem here?

2. let options = [1:”to do”, 2:”not to do”]; let option = options[1] - What’s the type of option?

3. let colorPref = account.secondName!.colorPref! - secondName and colorPref are optionals. How do you write this with Optional Chaining?

4. let zip = customer.address?.postalCode - Here type of postalCode is Int; and that of address is Address? in the Customer struct. What’s the type of zip?

5. var nickname: String? = “”; let count = nickname?.characters.count — What would be the value of count?

Article Series
Previous Article: Swift - Optional Chaining	This article is part of the Series: Swift - Optionals	Next Article: Swift - Summary of ?, !, and ?? in Optionals

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