How to Iterate Over a List in Reverse Order in Kotlin

How to Iterate Over a List in Reverse Order in Kotlin ?

Answer

To iterate over a list in reverse order in Kotlin, you can use the listIterator method combined with the hasPrevious and previous functions of the ListIterator class.

✐ Examples

1 Iterate Over a List in Reverse Order

In this example,

We create a list named listOfNumbers containing integer values.
We obtain a list iterator by calling the listIterator method on listOfNumbers.
We use a while loop with the hasPrevious function to iterate over the list in reverse order.
Inside the loop, we use the previous function to access each element and print it to standard output.

Kotlin Program

fun main() {
    val listOfNumbers = listOf(1, 2, 3, 4, 5)
    val listIterator = listOfNumbers.listIterator(listOfNumbers.size)
    while (listIterator.hasPrevious()) {
        val number = listIterator.previous()
        println(number)
    }
}

Output

2 Iterate Over a List of Strings in Reverse Order

In this example,

We create a list named listOfStrings containing string values.
We obtain a list iterator by calling the listIterator method on listOfStrings.
We use a while loop with the hasPrevious function to iterate over the list in reverse order.
Inside the loop, we use the previous function to access each element and print it to standard output.

Kotlin Program

fun main() {
    val listOfStrings = listOf("apple", "banana", "orange", "grape", "kiwi")
    val listIterator = listOfStrings.listIterator(listOfStrings.size)
    while (listIterator.hasPrevious()) {
        val fruit = listIterator.previous()
        println(fruit)
    }
}

Output

kiwi
grape
orange
banana
apple

Summary

In this tutorial, we learned How to Iterate Over a List in Reverse Order in Kotlin language with well detailed examples.

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How to Iterate Over a List in Reverse Order in Kotlin

How to Iterate Over a List in Reverse Order in Kotlin ?

Answer

✐ Examples

1 Iterate Over a List in Reverse Order

Kotlin Program

Output

2 Iterate Over a List of Strings in Reverse Order

Kotlin Program

Output

Summary

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