Limitations and best practices in Swift - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a constant in Swift.

Swift

let [1] = 10

Drag options to blanks, or click blank then click option'

Afunc

Bvar

Cscore

Dclass

Attempts:

3 left

💡 Hint

Common Mistakes

Using keywords like var or func as names.

Leaving the blank empty.

In Swift, let declares a constant. Here, score is the name of the constant.

2fill in blank

medium

Complete the code to safely unwrap an optional using if-let.

Swift

if let value = optional[1] {
    print(value)
}

Drag options to blanks, or click blank then click option'

AValue

B.

C!

D?

Attempts:

3 left

💡 Hint

Common Mistakes

Using ! which forces unwrap and can cause crashes.

Using uppercase letters or dots incorrectly.

The ? after optional means it might have a value. if let safely unwraps it.

3fill in blank

hard

Fix the error in the function declaration to follow Swift best practices.

Swift

func greet(name: String[1] String) {
    print("Hello, \(name)!")
}

Drag options to blanks, or click blank then click option'

A:

B,

C;

D.

Attempts:

3 left

💡 Hint

Common Mistakes

Using colons or semicolons instead of commas.

Missing commas causing syntax errors.

Function parameters are separated by commas , in Swift.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that filters keys with values greater than 5.

Swift

let filtered = dictionary.filter { $0.value [1] 5 }.[2] { $0.key: $0.value }

Drag options to blanks, or click blank then click option'

A>

Bmap

Cfilter

Dreduce

Attempts:

3 left

💡 Hint

Common Mistakes

Using filter twice instead of map.

Using wrong comparison operators.

Use filter to select items where value is greater than 5, then map to create a dictionary from filtered pairs.

5fill in blank

hard

Fill all three blanks to create a safe optional binding with a guard statement.

Swift

guard let [1] = optionalValue [2] else {
    [3]
}

Drag options to blanks, or click blank then click option'

Avalue

Belse

Creturn

Dif

Attempts:

3 left

💡 Hint

Common Mistakes

Using if instead of else.

Not returning or exiting in the else block.

guard let unwraps optionalValue safely. The else block runs if unwrapping fails, and return exits the function early.