Enums, or enumerations, are a powerful feature in Swift that allows you to define a set of related values as a single type. Enums can be used to represent a set of options or states, and can make your code more readable and easier to maintain.
To create an enum in Swift, use the enum
keyword followed by the name of the enum. Inside the curly braces, you define the possible cases of the enum as comma-separated values:
enum Planet {
case mercury
case venus
case earth
case mars
case jupiter
case saturn
case uranus
case neptune
}
In this example, we've defined an enum called Planet
with possible cases for each of the eight planets in our solar system.
Once you've defined an enum, you can use it to define variables or parameters with the enum type:
var favoritePlanet: Planet = .earth
In this example, we've defined a variable called favoritePlanet
of type Planet
. We've set the initial value to .earth
, which is a case of the Planet
enum.
You can also use enums in switch statements to handle different cases:
func planetDescription(planet: Planet) -> String {
switch planet {
case .mercury:
return "The smallest planet in the solar system"
case .venus:
return "The hottest planet in the solar system"
case .earth:
return "The only known planet with life"
case .mars:
return "Also known as the Red Planet"
case .jupiter:
return "The largest planet in the solar system"
case .saturn:
return "Famous for its rings"
case .uranus:
return "The first planet discovered using a telescope"
case .neptune:
return "The farthest planet from the Sun"
}
}
let description = planetDescription(planet: .mars)
print(description) // Outputs "Also known as the Red Planet"
In this example, we've defined a function called planetDescription
that takes a parameter of type Planet
. In the switch statement inside the function, we handle each possible case of the enum and return a description of the planet. We then call the function with an argument of .mars
and print the result.
Enums are a powerful feature in Swift that can make your code more readable and easier to maintain. Using enums allows you to define a set of related values as a single type, and switch statements can be used to handle different cases of the enum. Try using enums in your next Swift project to see how they can simplify your code.