Collections (List, Map, Set) in Android Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a mutable list of strings named fruits.

Android Kotlin

val fruits = mutableListOf[1]

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

A{"Apple", "Banana"}

B<String>()

C["Apple", "Banana"]

D("Apple", "Banana")

Attempts:

3 left

💡 Hint

Common Mistakes

Using square brackets [] which is not valid syntax for list creation in Kotlin.

Using parentheses () without specifying the type.

Use mutableListOf() to create an empty mutable list of strings in Kotlin.

2fill in blank

medium

Complete the code to add the string "Orange" to the fruits list.

Android Kotlin

fruits.[1]("Orange")

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

Apush

Binsert

Cappend

Dadd

Attempts:

3 left

💡 Hint

Common Mistakes

Using append() which is not a Kotlin list method.

Using push() which is used in other languages like JavaScript.

In Kotlin, use the add() method to add an element to a mutable list.

3fill in blank

hard

Fix the error in the code to create a map with keys as strings and values as integers.

Android Kotlin

val scores = mapOf<String, Int>[1]("Alice" to 10, "Bob" to 8)

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

A(

B[

C{

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using square brackets [] which causes syntax errors.

Using curly braces {} which are for lambda expressions.

Use parentheses () to pass pairs to mapOf in Kotlin.

4fill in blank

hard

Fill both blanks to create a set of integers and add the number 5 to it.

Android Kotlin

val numbers = mutableSetOf[1](1, 2, 3)
numbers.[2](5)

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

A<Int>

Badd

Cappend

D()

Attempts:

3 left

💡 Hint

Common Mistakes

Using append() which is not a Kotlin method for sets.

Omitting the type specification which can cause type inference issues.

Use to specify the type and add() to add an element to a mutable set.

5fill in blank

hard

Fill all three blanks to create a map from strings to integers, add a new pair, and retrieve a value.

Android Kotlin

val ages = mutableMapOf[1]("John" to 25, "Jane" to 30)
ages.[2]("Mike", 20)
val age = ages[[3]]

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

A<String, Int>

Bput

C"Mike"

Dadd

Attempts:

3 left

💡 Hint

Common Mistakes

Using add() instead of put() to add to a map.

Using a variable instead of the string key when retrieving the value.

Use to specify map types, put() to add a pair, and the key "Mike" to retrieve the value.