【Swift 60秒】17 - Enum associated values

0x00 Lesson

As well as storing a simple value, enums can also store ​​associated​​​ values attached to each case. This lets you attach ​​additional​​ information to your enums so they can represent more nuanced data.

For example, we might define an enum that stores various kinds of activities:

enum Activity
  case bored
  case running
  case talking
  case singing
}

That lets us say that someone is talking, but we don’t know what they talking about, or we can know that someone is running, but we don’t know where they are running to.

Enum associated values let us add those additional details:

enum Activity{
  case bored
  case running (destination: String)
  case talking(topic: String)
  case singing (volume: Int)
}

Now we can be more precise - we can say that someone is taking about football:

let talking = Activity.talking(topic: "footbal")

0x01 Tips

Associated values let you attach extra properties to any or all of your enum cases.

0x02 我的小作品

欢迎体验我的作品之一：​​小五笔​​​ 五笔学习好帮手
​​App Store​​ 搜索即可~