Sort a String alphabetically in Kotlin

This article explores different ways to sort a String alphabetically in Kotlin.

1. Using `sort()` function

Since the String is immutable in Kotlin, it cannot be modified once created. The only plausible way to rearrange the characters of a string in sorted order is to get a new string. The idea is to convert the given string to a character array using the toCharArray() function and sort it using the sort() function. Then, pass the character array to the String constructor to get a new string.

fun main() {

var str = "BADC"

val chars = str.toCharArray()

chars.sort()

str = String(chars)

println(str)

}

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This can be done inline using a scope function, as shown below:

fun main() {

var str = "BADC"

str = str.toCharArray().apply { sort() }.joinToString("")

println(str)

}

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Or even shorter:

fun main() {

var str = "BADC"

str = String(str.toCharArray().apply { sort() })

println(str)

}

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2. Using `sorted()` function

Another option is to split the string with delimiter "" to get a list of characters in the String, which then can be sorted using the sorted() function. After sorting, join the array back into a string using the joinToString() function.

fun main() {

var str = "BADC"

str = str.split("").sorted().joinToString("")

println(str)

}

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That’s all about sorting a String alphabetically in Kotlin.

Sort a String alphabetically in Kotlin

1. Using sort() function

2. Using sorted() function

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1. Using `sort()` function

2. Using `sorted()` function