Given a dictionary of optional ages, write Swift code using if let to print the age only if it exists for the key "John".

hard📝 Application Q8 of 15

Swift - Optionals

Given a dictionary of optional ages, write Swift code using if let to print the age only if it exists for the key "John".
Which code snippet correctly does this?

Aif let age = ages["John"] { print("John's age is \(age)") }

Bif let age = ages[John] { print("John's age is \(age)") }

Cif let age = ages["John"]! { print("John's age is \(age)") }

Dif let age = ages["John"] ?? 0 { print("John's age is \(age)") }

Step-by-Step Solution

Solution:

Step 1: Access dictionary optional value
Accessing ages["John"] returns an optional Int.
Step 2: Use if let to unwrap safely
Using if let age = ages["John"] unwraps the optional if it exists.
Final Answer:
if let age = ages["John"] { print("John's age is \(age)") } -> Option A
Quick Check:
Optional dictionary value unwrapped with if let [OK]

Quick Trick: Use if let with dictionary[key] to unwrap optional values [OK]

Common Mistakes:

Using unquoted key in dictionary access
Force unwrapping with ! causing crash
Using nil coalescing inside if let

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More Swift Quizzes

Given a dictionary of optional ages, write Swift code using if let to print the age only if it exists for the key "John".

Step 1: Access dictionary optional value

Step 2: Use if let to unwrap safely

Final Answer:

Quick Check:

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