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Test: Swift - Optional Chaining
2. let options = [1:”to do”, 2:”not to do”]; let option = options[1] - What’s the type of option?
Results Congratulations! Correct Answer. You Answered: None. If you took the test, your answer will show up here. Correct Answer: let option: String? Explanation When a value is obtained from a Swift dictionary by using key, the value it returns will be of optional type. So, if the dictionary is of type [Int: String], then the returned value will be of String? type. This is done to facilitate returning a nil value if the key is not found. So, for example, in the above case options[3] will return a nil - a String? type will be able to accommodate this.Take the Test Take the complete test on this topic. You will be able to review answers to questions and get a test score.
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Test is Based on this Article
This article talks about optional chaining in swift where multiple optionals can be chained together and fail gracefully by returning nil when one of them is nil.
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Test on optional chaining to safely return a nil or non-nil value from a series of optionals chained together.
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