Dictionary creation and access in Swift - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create an empty dictionary named ages.

Swift

var ages: [String: Int] = [1]

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

A{}

B[:]

CArray()

D()

Attempts:

3 left

💡 Hint

Common Mistakes

Using curly braces {} is invalid syntax for a dictionary.

Using parentheses () or Array() creates other types, not dictionaries.

In Swift, an empty dictionary is created using [:]. This means no key-value pairs yet.

2fill in blank

medium

Complete the code to create a dictionary capitals with keys and values.

Swift

let capitals = [1]

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

A["France", "Paris", "Japan", "Tokyo"]

B("France": "Paris", "Japan": "Tokyo")

C{"France": "Paris", "Japan": "Tokyo"}

D["France": "Paris", "Japan": "Tokyo"]

Attempts:

3 left

💡 Hint

Common Mistakes

Using parentheses instead of square brackets.

Using curly braces which is invalid syntax for dictionaries.

Listing keys and values as a flat array.

Swift dictionaries use square brackets with key-value pairs separated by colons.

3fill in blank

hard

Fix the error in accessing the value for key "apple" in the dictionary fruitColors.

Swift

let color = fruitColors[1]"apple"

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

A(

B.get(

C[

D{

Attempts:

3 left

💡 Hint

Common Mistakes

Using parentheses or curly braces instead of square brackets.

Trying to use a method like .get() which is not available in Swift dictionaries.

In Swift, dictionary values are accessed using square brackets with the key inside.

4fill in blank

hard

Complete the code to create a dictionary scores with keys as player names and values as their scores.

Swift

var scores: [String: Int] = [1]

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

A["Alice": 10, "Bob": 15]

B{"Alice": 10, "Bob": 15}

C("Alice", 10, "Bob", 15)

D["Alice", 10, "Bob", 15]

Attempts:

3 left

💡 Hint

Common Mistakes

Using parentheses or curly braces instead of square brackets.

Listing keys and values as a flat list without colons.

Use square brackets with key-value pairs separated by colons to create a dictionary.

5fill in blank

hard

Complete the code to safely access the value for key "cat" in animalSounds and provide a default if missing.

Swift

let sound = animalSounds["cat"][1]"unknown"

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

A[

B??

C:

D]

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to close the square brackets.

Using colon instead of nil-coalescing operator for default values.

Not providing a default value causing optional type issues.

Access dictionary value with square brackets, then use the nil-coalescing operator ?? to provide a default. Close the brackets properly.