Also function behavior and use cases in Kotlin - Mini Project: Build & Apply

Understanding the Kotlin also Function

📖 Scenario: Imagine you are organizing a list of books and want to log some information while building the list. Kotlin's also function helps you do extra actions on an object without changing it.

🎯 Goal: You will create a list of book titles, use the also function to print each book as it is added, and finally print the full list.

📋 What You'll Learn

Create a mutable list of strings called books with initial titles

Create a variable newBook with a book title

Use the also function to print the newBook before adding it to books

Print the final books list

💡 Why This Matters

🌍 Real World

The <code>also</code> function is useful when you want to do extra work with an object, like logging or debugging, without changing the object itself.

💼 Career

Understanding <code>also</code> helps you write cleaner Kotlin code, which is valuable for Android development and backend Kotlin projects.

1

Create the initial list of books

Create a mutable list of strings called books with these exact titles: "Kotlin Basics", "Advanced Kotlin", and "Kotlin Coroutines".

Kotlin

# Create the mutable list called books with the given titles
# Your code here

Need a hint?

Use mutableListOf to create a list you can add to later.

2

Create a new book title variable

Create a variable called newBook and set it to the string "Kotlin Flow".

Kotlin

val books = mutableListOf("Kotlin Basics", "Advanced Kotlin", "Kotlin Coroutines")
# Create the variable newBook with the title "Kotlin Flow"
# Your code here

Need a hint?

Use val to create a read-only variable with the exact string.

3

Use also to print the new book before adding

Use the also function on newBook to print "Adding book: " followed by the book title, then add the book to the books list.

Kotlin

val books = mutableListOf("Kotlin Basics", "Advanced Kotlin", "Kotlin Coroutines")
val newBook = "Kotlin Flow"
# Use also on newBook to print and then add to books
# Your code here

Need a hint?

The also function lets you do something with the object (like print) and then returns it so you can add it to the list.

4

Print the final list of books

Write a println statement to print the books list.

Kotlin

val books = mutableListOf("Kotlin Basics", "Advanced Kotlin", "Kotlin Coroutines")
val newBook = "Kotlin Flow"
newBook.also { println("Adding book: $it") }.let { books.add(it) }
# Print the books list
# Your code here

Need a hint?

Use println(books) to show the full list after adding the new book.