Skip to main content

How to create and initialize an array in Kotlin

How to create and initialize an array in Kotlin.

Here's a step-by-step tutorial on how to create and initialize an array in Kotlin:

Step 1: Declare the array variable​

To create an array in Kotlin, you first need to declare a variable of array type. You can do this by specifying the element type followed by square brackets. For example, to create an array of integers, you would declare a variable like this:

val numbers: IntArray

Step 2: Initialize the array using the constructor​

After declaring the array variable, you can initialize it using the array constructor. The array constructor is called by using the IntArray() function and specifying the size of the array in parentheses. For example, to create an array of 5 integers, you would initialize it like this:

val numbers: IntArray = IntArray(5)

Step 3: Assign values to the array elements​

Once the array is initialized, you can assign values to its elements. To access an element in the array, you can use the index inside square brackets. The index starts at 0 for the first element and goes up to array.size - 1 for the last element. Here's an example of assigning values to the elements of the array we created earlier:

numbers[0] = 10
numbers[1] = 20
numbers[2] = 30
numbers[3] = 40
numbers[4] = 50

Step 4: Initialize the array with values​

Alternatively, you can initialize the array with specific values at the time of declaration. To do this, you can use the intArrayOf() function and provide the values inside the parentheses, separated by commas. Here's an example:

val numbers: IntArray = intArrayOf(10, 20, 30, 40, 50)

Step 5: Accessing array elements​

To access the elements of the array, you can use the same square bracket notation as when assigning values. For example, to print the value of the third element in the array, you would do:

println(numbers[2]) // Output: 30

Step 6: Array size and bounds​

To get the size of the array, you can use the size property. For example:

println(numbers.size) // Output: 5

It's important to note that array indices start at 0 and end at array.size - 1. If you try to access an element outside this range, it will result in an ArrayIndexOutOfBoundsException.

Step 7: Iterate over the array​

To iterate over the elements of an array, you can use a loop. One way to do this is by using a for loop with the indices property. Here's an example:

for (i in numbers.indices) {
    println(numbers[i])
}

This will print each element of the array on a separate line.

That's it! You now know how to create and initialize an array in Kotlin. You can use these steps as a guide when working with arrays in your Kotlin projects.