0x00 Lesson

Sometimes you need to be able to ​​assign values​​ to enums so they have meaning. This lets you create them dynamically, and also use them in different ways.

For example, you might create a Planet enum that stores integer values for each of its cases:

enum Planet: Int {
  case mercury
  case venus
  case earth
  case mars
}

Swift will automatically ​​assign​​ each of those a number starting from ​​0​​​, and you can use that ​​number​​ to create an instance of the appropriate enum case. For example, earth will be given the number 2, so you can write this:

let earth = Planet(rawValue: 2)

If you want, you can assign one or more cases a specific value, and Swift will generate the rest. It’s not very natural for us to think of Earth as the second planet, so you could write this:

enum Planet: Int {
  case mercury = 1
  case venus
  case earth
  case mars
}

Now Swift will assign 1 to mercury and count upwards from there, meaning that earth is now the ​​third​​ planet.

0x01 Tips

Raw values let us give each of our enum cases a value so they are more than just names.

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