Infix functions for readable calls in Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare an infix function named shout for the String class.

Kotlin

infix fun String.[1]() = this.uppercase() + "!"

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Ashout

Bprint

Clowercase

Drepeat

Attempts:

3 left

💡 Hint

Common Mistakes

Using a function name that is not descriptive of the action.

Forgetting to use the infix keyword.

The infix function is named shout to match the intended usage.

2fill in blank

medium

Complete the code to call the infix function shout on the string "hello".

Kotlin

val loud = "hello" [1] shout()

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Ainfix

B.

C->

D!!

Attempts:

3 left

💡 Hint

Common Mistakes

Using the infix keyword in the call instead of the declaration.

Using invalid operators like -> or !!.

Infix functions are called without dots or parentheses, but since shout has no parameters, parentheses are optional. Here, the dot is needed to call the function normally.

3fill in blank

hard

Fix the error in the infix function declaration by completing the code.

Kotlin

infix fun Int.[1](times: Int): Int = this * times

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AmultiplyBy

Brepeat

Ctimes

Dmultiply

Attempts:

3 left

💡 Hint

Common Mistakes

Using a function name that conflicts with existing Kotlin functions.

Choosing a name that is not intuitive for multiplication.

The function name times is a common and readable infix function name for multiplication.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that maps words to their uppercase form only if the word length is greater than 3.

Kotlin

val result = words.associateWith { it.[1]() }.filter { it.key.length [2] 3 }

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Auppercase

B>

C<

Dlowercase

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase() instead of uppercase().

Using the wrong comparison operator.

The uppercase() function converts strings to uppercase, and the filter keeps words longer than 3 characters.

5fill in blank

hard

Fill all three blanks to create a map from uppercase keys to their lengths, only for words longer than 4 characters.

Kotlin

val map = words.filter { it.length [1] 4 }.associateBy( [2] ) { it.[3] }

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A>

Bit.uppercase()

Clength

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong comparison operator.

Using the word itself as key instead of uppercase.

Using a function name instead of a property for length.

Filter words longer than 4, use uppercase words as keys, and map to their length.