String concatenation vs templates in Kotlin - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to concatenate two strings using the + operator.

Kotlin

val greeting = "Hello, " [1] "World!"

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

A+

B/

C*

D-

Attempts:

3 left

💡 Hint

Common Mistakes

Using arithmetic operators like - or * instead of + for strings.

In Kotlin, the + operator is used to join (concatenate) strings.

2fill in blank

medium

Complete the code to use a string template to insert the variable name into the greeting.

Kotlin

val name = "Alice"
val greeting = "Hello, [1]!"

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

A{name}

Bname

C"name"

D$name

Attempts:

3 left

💡 Hint

Common Mistakes

Writing the variable name without $ inside the string.

Using curly braces without $.

In Kotlin, string templates use the $ symbol before a variable name to insert its value inside a string.

3fill in blank

hard

Fix the error in the string template to correctly include the variable age.

Kotlin

val age = 30
val message = "I am [1] years old."

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

A${age}

Bage

C$age

D"age"

Attempts:

3 left

💡 Hint

Common Mistakes

Using $variable without braces when followed by text.

Writing variable name without $.

When inserting expressions or variables in Kotlin strings, use ${variable} to clearly mark the variable inside the string.

4fill in blank

hard

Fill both blanks to create a map of words to their lengths, using string templates and a condition.

Kotlin

val words = listOf("apple", "bat", "carrot")
val lengths = {word: [1] for word in words if word.length [2] 3}

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

Aword.length

B>

C<

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using word instead of word.length for the value.

Using wrong comparison operators like < or ==.

The map uses word.length to get the length of each word. The condition filters words longer than 3 characters using >.

5fill in blank

hard

Fill all three blanks to create a message using string templates with expressions.

Kotlin

val x = 5
val y = 10
val message = "Sum of [1] and [2] is [3]"

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

Ax

By

C${x + y}

D$x

Attempts:

3 left

💡 Hint

Common Mistakes

Not using $ before variables inside strings.

Not using ${} for expressions.

Use $x and $y to insert variables, and ${x + y} to insert the sum expression inside the string.