6 Ways to Print an Array in Kotlin with example

6 Ways to Print an Array in Kotlin with example

Let’s declare an array in Kotlin

    val array = arrayOf("a", "b", "c", "d")

Now, print the array using the println function:

println(array)

The output is:

[Ljava.lang.String;@7cc355be

Inspecting the values of an array during debugging becomes challenging with this output. So, how can you print your Kotlin array object without getting ”type@hashcode?

This tutorial explains how to print the array elements to the console.

How to Print Array Elements in Kotlin with Examples

There are multiple ways to log an array of items in Kotlin.

Use a For Loop

The for in loop iterates through each element in an array and prints each element to the console using the println function.

It’s a native and basic way to iterate through each element.

import java.util.Arrays

fun main() {
    val array = arrayOf("a", "b", "c", "d")
    for (item in array) {
        println(item)
    }
}

Output:

a
b
c
d

Use Arrays.toString Method

The Arrays class has a built-in toString method that takes an array variable and prints its values. It’s an easy way to print without iterating through each element.

import java.util.Arrays

fun main() {
    val array = arrayOf("a", "b", "c", "d")
    println(Arrays.toString(array))
}

Output

[a, b, c, d]

Use the Array joinToString method

The joinToString method takes a separator, iterates through each element, appends, and returns the string.


fun main() {
    val array = arrayOf("a", "b", "c", "d")
    println(array.joinToString(" "))
}

Use the forEach Method

The forEach🔗 method takes a lambda expression.

It iterates through each element, applies a function, and calls the body inside it.

fun main() {
    val array = arrayOf("a", "b", "c", "d")
    // lambda expression
    array.forEach { println(it) }
    //using method reference syntax
    array.forEach(System.out::print)
}

When the above program prints

a
b
c
d
abcd

Use the Array contentToString Function

The contentToString function prints the array elements by displaying the string representation of each element.

fun main() {
    val array = arrayOf("a", "b", "c", "d")
    println(array.contentToString())// [a, b, c, d]

}

How to Print Array of Strings or Integers

Arrays of strings or integers can be printed using the approaches mentioned above.

Here is an example:

fun main() {
    val numbers = intArrayOf(11, 12, 13, 14, 15)
    println(numbers.contentToString())

}

Outputs:

[11, 12, 13, 14, 15]

Conclusion

This tutorial explored various methods for printing array elements in Kotlin, providing flexibility based on different approaches.

Developers can choose from options such as

  • using a for loop for a native approach,
  • leveraging Arrays.toString for simplicity,
  • employing joinToString for customization,
  • utilizing forEach for lambda expression functionality,
  • or using contentToString for string representation.

The diverse set of methods caters to different needs, allowing developers to select the most suitable approach when working with arrays in Kotlin.