How to use enum in Swift

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Enumerations defines a type for group of related values.

Enumerations (enum) enables you to write code in a type safe way. Enum is very useful while defining common type of values. You don’t have to provide value while defining enum.

Syntax

You can declare enumerations with enum keyword.

enum SomeEnumerations {
  
}

Here is a basic example of defining enumeration. You can use case keyword to define new enumeration cases.

enum Direction {
  case north
  case south
  case east
  case west
}

You can also define cases in single line rather than multiple lines. For example,

enum DaysOfWeek {
  case sunday, monday, tuesday, wednesday, thursday, friday, saturday
}

You can assign enum value to new variable in following way.

var day = DaysOfWeek.sunday

Matching enum values using switch statement

You can match value of enum using switch statement in following way.

var direction = Direction.west

switch direction {
  case .east:
    print("Marked with E")
  case .west:
    print("Marked with W")
  case .north:
    print("Marked with N")
  case .south:
    print("Marked with S")
  default:
    print("Direction not found")
}

Iterating over enumeration cases

You can perform iteration over enum cases using CaseIterable. You have to write CaseIterable after the enum name. For example,

enum Season: CaseIterable {
  case summer, winter, spring, autumn
} 

let typeofSeasons = Season.allcases.count
print("There are \(typeofSeasons) type of seasons.")

You can iterate over all cases of enum using for-in loop.

for season in Season.allCases {
  print(season)
} 

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