In Kotlin, range provides a powerful tool that represents a consecutive succession of values that can often be used in conjunction with conditionals.

In Kotlin, ranges are created using the .. operator:

StartingValue..EndingValue

The range will start at the value that appears before .. and will continue until it reaches the value that appears after ...

We can check if values are contained within a specified range with the help of the in keyword:

var num = 5

if (num in 1..10) {
  println("This value is between 1 and 10.")
}

The in keyword is used to check if a value exists inside of a collection or range. The program above checks if num exists within the range of 1 through 10.

We can also check if a character, or Char, value appears inside of a range:

var letter = 'c'

when (letter) {
  in 'a'..'m' -> println("Letter is in 1st half of alphabet.")
  in 'n'..'z' -> println("Letter is in 2nd half of alphabet.")
  else -> println("Not a valid value")
}

Note: Letter ranges are case-sensitive.