Type checking with is operator in Kotlin - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check if the variable obj is a String.

Kotlin

if (obj [1] String) {
    println("It's a string")
}

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

A==

Bequals

Cinstanceof

Dis

Attempts:

3 left

💡 Hint

Common Mistakes

Using '==' instead of 'is' for type checking.

Using 'instanceof' which is Java syntax, not Kotlin.

The is operator in Kotlin checks if an object is of a specific type.

2fill in blank

medium

Complete the code to check if value is NOT an Int.

Kotlin

if (value ![1] Int) {
    println("Not an integer")
}

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

Ais

Attempts:

3 left

💡 Hint

Common Mistakes

Placing the exclamation mark after 'is' instead of before.

Using '!=' instead of '!is' for type checking.

The correct syntax to check if a value is NOT a type is to use !is.

3fill in blank

hard

Fix the error in the code to check if item is a Double.

Kotlin

if (item [1] Double) {
    println("It's a double")
}

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

A==

Bequals

Cis

Dinstanceof

Attempts:

3 left

💡 Hint

Common Mistakes

Using Java's 'instanceof' instead of Kotlin's 'is'.

Using '==' which compares values, not types.

Use the is operator to check the type in Kotlin.

4fill in blank

hard

Fill both blanks to check if data is a String and print its length.

Kotlin

if (data [1] String) {
    println(data[2]length)
}

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

Ais

B==

C?.

D!!

Attempts:

3 left

💡 Hint

Common Mistakes

Using '==' instead of 'is' for type checking.

Using '.' or '?.' instead of '!!' which is appropriate after type check.

Use is to check type and non-null assertion operator !! to access length safely after type check.

5fill in blank

hard

Fill all three blanks to check if input is NOT a List and print a message.

Kotlin

if (input [1] [2] [3]) {
    println("Input is not a list")
}

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

Ais

BList

C)

D!

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting the exclamation mark to negate the check.

Not closing the if condition with a parenthesis.

Use '!is' to check NOT a type, specify 'List', and close the if condition with ')'.