Swift - Operators and Expressions
Given nested optionals
let data: Int?? = 5, which expression safely unwraps to get the Int value?Given nested optionals let data: Int?? = 5, which expression safely unwraps to get the Int value?
hard📝 Application Q9 of 15
Step-by-Step Solution
Solution:
Step 1: Understand nested optionals
Int??means optional of optional Int, so unwrapping requires two steps.Step 2: Use flatMap to unwrap inner optional safely
data?.flatMap { $0 }unwraps outer optional and then inner optional safely.Step 3: Provide default with ??
If any unwrap fails,?? 0returns 0.Final Answer:
data?.flatMap { $0 } ?? 0 -> Option DQuick Check:
Nested optional unwrap needs flatMap + ?? [OK]
Quick Trick: Use flatMap to unwrap nested optionals safely [OK]
Common Mistakes:
- Using ?? once only unwraps outer optional
- Using ! causes crash if nil
- Incorrect syntax with double ?? operator
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