Iterating collections with forEach in Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to print each number in the list using forEach.

Kotlin

val numbers = listOf(1, 2, 3, 4, 5)
numbers.forEach { [1] -> println([1]) }

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

Anumber

Bitem

Cnum

Dvalue

Attempts:

3 left

💡 Hint

Common Mistakes

Using a keyword or invalid variable name as the lambda parameter.

Leaving the lambda parameter blank.

The lambda parameter name can be any valid identifier. Here, number is used to represent each element.

2fill in blank

medium

Complete the code to print each fruit in uppercase using forEach.

Kotlin

val fruits = listOf("apple", "banana", "cherry")
fruits.forEach { [1] -> println([1].uppercase()) }

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

Aitem

Bfruits

Cfruit

Df

Attempts:

3 left

💡 Hint

Common Mistakes

Using the plural 'fruits' as the lambda parameter.

Using a variable name not matching the context.

The lambda parameter fruit represents each element in the list fruits.

3fill in blank

hard

Fix the error in the forEach lambda parameter to correctly print each name.

Kotlin

val names = listOf("Anna", "Bob", "Cara")
names.forEach { [1] -> println([1]) }

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

Alist

Bname

Cn

Dnames

Attempts:

3 left

💡 Hint

Common Mistakes

Using the collection name 'names' as the lambda parameter.

Using unrelated variable names.

The lambda parameter should be a single element, so name is correct. Using names (plural) causes confusion and errors.

4fill in blank

hard

Fill both blanks to create a map of word lengths for words longer than 3 characters.

Kotlin

val words = listOf("cat", "house", "tree", "a", "elephant")
val lengths = words.filter { it.length [1] 3 }.associateWith { [2].length }

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A>

Bword

C<

Dit

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' instead of '>' in the filter condition.

Using 'word' instead of 'it' inside associateWith.

The filter uses it.length > 3 to select words longer than 3 characters. The associateWith uses it.length to map each word to its length.

5fill in blank

hard

Fill all three blanks to create a map of uppercase keys and their lengths for words starting with 'a'.

Kotlin

val words = listOf("apple", "banana", "apricot", "cherry", "avocado")
val result = words.filter { [1].startsWith("a") }.associateBy([2].uppercase()) { [3].length }

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

Ait

Bword

Dw

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names inconsistently.

Using 'it' in associateBy lambdas when a named parameter is expected.

In the filter, it represents each word. In associateBy, word.uppercase() is the key, and word.length is the value.