Equality (== structural vs === referential) in Kotlin - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check if two strings have the same content using structural equality.

Kotlin

val a = "hello"
val b = "hello"
println(a [1] b)

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Aequals

B===

C!=

D==

Attempts:

3 left

💡 Hint

Common Mistakes

Using === instead of == for content comparison.

In Kotlin, == checks if two objects have the same content (structural equality).

2fill in blank

medium

Complete the code to check if two string variables point to the exact same object using referential equality.

Kotlin

val x = "world"
val y = x
println(x [1] y)

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

A===

B==

Cequals

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using == instead of === to check reference equality.

The === operator checks if two references point to the same object (referential equality).

3fill in blank

hard

Fix the error in the code to correctly compare two different String objects for content equality.

Kotlin

val s1 = String(charArrayOf('k', 'o', 't', 'l', 'i', 'n'))
val s2 = String(charArrayOf('k', 'o', 't', 'l', 'i', 'n'))
println(s1 [1] s2)

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

A===

Bequals()

C==

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using === instead of == for content comparison.

Use == to compare the content of two different String objects in Kotlin.

4fill in blank

hard

Fill both blanks to create a map of words to their lengths, but only include words with length greater than 3.

Kotlin

val words = listOf("cat", "kotlin", "dog", "java")
val lengths = words.associateWith { it.[1] }
val filtered = lengths.filter { it.value [2] 3 }

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Alength

B>

C<

Dcount

Attempts:

3 left

💡 Hint

Common Mistakes

Using < instead of > in the filter condition.

Use length to get the length of each word, and filter with > to keep words longer than 3.

5fill in blank

hard

Fill all three blanks to create a map of uppercase words to their lengths, including only words with length greater than 3.

Kotlin

val words = listOf("apple", "bat", "carrot", "dog")
val result = words.associate { it.[1]() to it.[2] }
val filtered = result.filter { it.value [3] 3 }

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

Auppercase

Blength

C>

DtoUpperCase

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'uppercase' property instead of 'toUpperCase()' function.

Use toUpperCase() to convert words to uppercase, length for their length, and > to filter lengths greater than 3.