I want to create an extension function of String which takes a String and returns a new String with the characters as the first, but sorted in ascending order. How can I do this? I am new to Kotlin.
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5 Answers
fun String.ascending() = String(toCharArray().sortedArray())
Then:
println("14q36w25e".ascending()) // output "123456eqw"
Comments
Extension function for printing characters of a string in ascending order
Way 1:
fun String.sortStringAlphabetically() = toCharArray().sortedArray())
Way 2:
fun String.sortStringAlphabetically() = toCharArray().sortedArrayDescending().reversedArray()
Way 3:
fun String.sortStringAlphabetically() = toCharArray().sorted().joinToString(""))
Way 4:
fun String.sortStringAlphabetically() = toCharArray().sortedBy{ it }.joinToString(""))
Then you can use this extension function by the below code:
fun main(args: Array<String>) {
print("41hjhfaf".sortStringAlphabetically())
}
Output: 14affhhj
Comments
You can combine built in extensions to do it quickly:
fun String.sortedAlphabetically() = toCharArray().apply { sort() }
First you get array of underlying characters, then you apply sort to that array and return it. You are free to cast result .toString() if You need.
2 Comments
crgarridos
why do you use the apply ? why not
toCharArray().sort() directly ?
Pawel
sort() returns Unit, apply returns receiver object (CharArray).I have one more:
fun String.inAscending(): String = toMutableList().sortedBy { it }.joinToString("")
And better:
fun String.ascending(): String = toMutableList().sorted().joinToString("")
Comments
In my opinion, do it in kotlin way i.e
fun String.sortAscending() = toCharArray().sortedBy{ it }.joinToString("")
