Array creation and usage in Kotlin - Cheat Sheet & Quick Revision

Recall & Review

beginner

How do you create an array of integers with values 1, 2, and 3 in Kotlin?

You can create it using val numbers = arrayOf(1, 2, 3). This creates an array holding the integers 1, 2, and 3.

beginner

How do you access the second element of an array named arr in Kotlin?

Use arr[1] because Kotlin arrays use zero-based indexing, so the first element is at index 0.

intermediate

What happens if you try to access an index outside the array bounds in Kotlin?

Kotlin throws an ArrayIndexOutOfBoundsException. This means you tried to get or set a position that does not exist in the array.

beginner

How can you create an array of size 5 filled with zeros in Kotlin?

Use val zeros = IntArray(5). This creates an integer array of size 5 where all elements are 0 by default.

beginner

How do you change the value of the third element in an array arr to 10?

Assign the value using arr[2] = 10. Remember, arrays start at index 0, so the third element is at index 2.

Which of the following creates an array of strings in Kotlin?

A val arr = ["apple", "banana", "cherry"]

B val arr = arrayOf("apple", "banana", "cherry")

C val arr = new Array("apple", "banana", "cherry")

D val arr = ArrayList("apple", "banana", "cherry")

In Kotlin, arrayOf() creates an array. Square brackets or new keyword are not used for arrays.

What is the index of the first element in a Kotlin array?

A 0

B Depends on the array size

C -1

D 1

Kotlin arrays use zero-based indexing, so the first element is at index 0.

How do you find the size of an array named arr in Kotlin?

A arr.size

B arr.count()

C arr.length

D arr.length()

Use arr.size to get the number of elements in a Kotlin array.

What will happen if you try to access arr[5] when arr has 5 elements?

A Returns the last element

B Returns null

C Throws ArrayIndexOutOfBoundsException

D Creates a new element at index 5

Accessing index 5 in a 5-element array is out of bounds (indices 0 to 4), so Kotlin throws an exception.

Which Kotlin function creates an integer array of size 3 with all elements initialized to 7?

A Array(3, 7)

B arrayOf(7, 7, 7)

C IntArray(3, {7})

D IntArray(3) { 7 }

Use IntArray(3) { 7 } to create an integer array of size 3 where each element is 7.

Explain how to create and access elements in a Kotlin array.

Think about how you make the array and how you get values from it.

Describe what happens if you try to access an index outside the array's range in Kotlin.

What error does Kotlin give when you go too far?