Dictionary methods and default values in Swift - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to get the value for key "apple" from the dictionary.

Swift

let fruits = ["apple": 3, "banana": 5]
let count = fruits[[1]]

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

A"orange"

B"apple"

C"banana"

D"grape"

Attempts:

3 left

💡 Hint

Common Mistakes

Using a key that does not exist in the dictionary.

Forgetting to put the key inside quotes.

The key "apple" is used to access its value in the dictionary.

2fill in blank

medium

Complete the code to provide a default value of 0 when the key is missing.

Swift

let fruits = ["apple": 3, "banana": 5]
let count = fruits["orange", default: [1]]

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

Anil

B5

C-1

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using nil as a default value which is not allowed here.

Using a default value that does not match the dictionary's value type.

Using default: 0 returns 0 if the key is not found.

3fill in blank

hard

Fix the error in updating the dictionary value safely.

Swift

var fruits = ["apple": 3, "banana": 5]
fruits["apple"] = fruits["apple"]! [1] 2

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

A+

B-

C*

D/

Attempts:

3 left

💡 Hint

Common Mistakes

Using subtraction or multiplication instead of addition.

Forgetting to unwrap the optional value before adding.

We add 2 to the existing value for key "apple".

4fill in blank

hard

Fill both blanks to create a dictionary with squares of numbers greater than 3.

Swift

let squares = [[1]: [2] for num in 1...5 if num > 3]

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

Anum

Bnum * num

Cnum + num

Dnum - 1

Attempts:

3 left

💡 Hint

Common Mistakes

Using addition or subtraction instead of multiplication for squares.

Using the wrong variable as key or value.

The dictionary keys are numbers and values are their squares for numbers greater than 3.

5fill in blank

hard

Fill all three blanks to filter dictionary items with values greater than 4 and map keys to uppercase.

Swift

let fruits = ["apple": 3, "banana": 5, "cherry": 7]
let filtered = [[1]: [2] for (key, value) in fruits where value [3] 4]

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

Akey.uppercased()

Bvalue

C>

Dkey

Attempts:

3 left

💡 Hint

Common Mistakes

Not converting keys to uppercase.

Using wrong comparison operator or value.

Keys are converted to uppercase, values are kept, and only items with values greater than 4 are included.