Published Oct 28, 2023
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The .compareTo() method in Kotlin is used to compare two strings lexicographically, meaning it compares the strings character by character based on their Unicode values. It helps determine the relative order of two strings in a dictionary or alphabetically. This method is commonly employed for sorting strings or performing string comparisons.


  • stringOne: The first string to be compared.
  • stringTwo: The second string to be compared.

If stringOne comes before stringTwo lexicographically, .compareTo() returns a negative value. If they are equal, it returns 0. If stringOne comes after stringTwo lexicographically, .compareTo() returns a positive value.


This example shows how to use the .compareTo() method to two strings:

fun main() {
val stringOne = "apple"
val stringTwo = "banana"
val result = stringOne.compareTo(stringTwo)
if (result < 0) {
println("$stringOne comes before $stringTwo")
} else if (result == 0) {
println("$stringOne and $stringTwo are the same")
} else {
println("$stringOne comes after $stringTwo")

The code will return the following output:

apple comes before banana

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