Careeroza

Enum Basics

A Fixed Set of Values

An enum class defines a type with a fixed list of values: days of the week, order statuses, payment modes. Using an enum instead of strings like "pending" prevents typos and lets the compiler check your when expressions.

Example

enum class Direction { NORTH, SOUTH, EAST, WEST }

fun main() {
    val d = Direction.EAST
    println(d)               // name
    println(d.name)
    println(d.ordinal)       // position, starting at 0
    println(Direction.entries)           // all values (Kotlin 1.9+)
    println(Direction.valueOf("WEST"))   // from a string
}

Output

EAST
EAST
2
[NORTH, SOUTH, EAST, WEST]
WEST

Parsing Safely

Example

valueOf throws for unknown names. For user or server input, search the entries instead.

enum class Size { S, M, L, XL }

fun parseSize(text: String): Size? = Size.entries.find { it.name.equals(text, ignoreCase = true) }

fun main() {
    println(parseSize("xl"))
    println(parseSize("XXL"))
    println(enumValues<Size>().joinToString())
}

Output

XL
null
S, M, L, XL