Kotlin Loops: Simplify Iteration with Ranges, Arrays, and More

Mastering the Art of Loops in Kotlin

A Fresh Approach to Iteration

Unlike its counterparts in Java and other languages, Kotlin takes a unique stance on traditional for loops. Instead, it leverages the power of iterators to navigate through ranges, arrays, maps, and more.

Unleashing the Power of Ranges

The syntax of Kotlin’s for loop is designed to simplify iteration. Let’s dive into an example that showcases its capabilities:

kotlin
for (item in 1..10) {
println(item)
}


Output: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10

Notice how the loop effortlessly iterates through the range, printing each individual item. When the body of the loop consists of a single statement, curly braces become optional.

Range Mastery: Multiple Iteration Methods

But that’s not all! You can iterate through a range using various techniques. For instance:

kotlin
for (item in 1..10 step 2) {
println(item)
}


Output: 1, 3, 5, 7, 9

Or, if you prefer:

kotlin
for (item in 10 downTo 1) {
println(item)
}


Output: 10, 9, 8, 7, 6, 5, 4, 3, 2, 1

Arrays: The Next Iteration

Now, let’s shift our focus to arrays. Iterating through a String array is a breeze:

kotlin
val languages = arrayOf("Kotlin", "Java", "Python")
for (language in languages) {
println(language)
}


Output: Kotlin, Java, Python

But what if you need to access the index of each element? No problem!

kotlin
for (index in languages.indices) {
println("Index: $index, Value: ${languages[index]}")
}


Output: Index: 0, Value: Kotlin, Index: 1, Value: Java, Index: 2, Value: Python

String Iteration: A World of Possibilities

Similar to arrays, you can iterate through a String with ease:

kotlin
val helloWorld = "Hello, World!"
for (char in helloWorld) {
println(char)
}


Output: H, e, l, l, o,,, , W, o, r, l, d,!

Or, if you prefer to access the index:

kotlin
for (index in helloWorld.indices) {
println("Index: $index, Value: ${helloWorld[index]}")
}


Output: Index: 0, Value: H, Index: 1, Value: e,…, Index: 12, Value:!

Maps: The Final Frontier

Stay tuned for our upcoming article on iterating over maps using Kotlin’s for loop. The possibilities are endless!