Consider this function that uses guard let inside a loop:

hard📝 Application Q9 of 15

Swift - Optionals

Consider this function that uses guard let inside a loop:

func printNames(_ names: [String?]) {
    for name in names {
        guard let validName = name else {
            print("Invalid name")
            continue
        }
        print(validName)
    }
}
printNames(["Anna", nil, "Bob"])

What will be the output?

AInvalid name\nInvalid name\nInvalid name

BAnna\nBob

CAnna\nInvalid name\nBob

DAnna\nInvalid name

Step-by-Step Solution

Solution:

Step 1: Analyze loop with guard let
For each name, guard let unwraps or prints "Invalid name" and continues to next iteration.
Step 2: Trace output for input array
"Anna" unwraps and prints, nil triggers "Invalid name", "Bob" unwraps and prints.
Final Answer:
Anna\nInvalid name\nBob -> Option C
Quick Check:
guard let with continue skips invalid optionals [OK]

Quick Trick: Use continue in guard else to skip invalid loop items [OK]

Common Mistakes:

Assuming loop stops on nil
Expecting no output for nil
Confusing continue with return

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More Swift Quizzes

Consider this function that uses guard let inside a loop:

Step 1: Analyze loop with guard let

Step 2: Trace output for input array

Final Answer:

Quick Check:

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