在swift 4.0中使用枚举为数组下标

iOS 11.x Swift 4.0

这不会编译，因为您不能用emum为数组下标，看起来是这样吗？有没有一种我可以用的可以用的

enum axis:Int {
  case x = 0
  case y = 1
}

var cords = [[10,21],[23,11],[42,12],[31,76]]
var smallestCord:Int = Int.max
var smallestSet:[Int] = []
for cord in cords {
  if cord[axis.x] < smallestCord {
    smallestCord = cord[axis.x]
    smallestSet = cord
  }
}
print("\(smallestCord) \(smallestSet)")

---

您应该使用rawValue而不是enum实例本身，例如cord[axis.x.rawValue]而不是cord[axis.x]。阅读更多信息。

您可以通过向数组添加扩展来实现，但这是您可以做的事情，而不是您应该做的事情

extension Array {
    subscript(index: axis) -> Element {
        return self[index.rawValue]
    }
}

您应该做的是定义适当的数据结构来封装数据：

struct Point {
    var x: Int
    var y: Int

    // For when you need to convert it to array to pass into other functions
    func toArray() -> [Int] {
        return [x, y]
    }
}

let cords = [
    Point(x: 10, y: 21),
    Point(x: 23, y: 11),
    Point(x: 42, y: 12),
    Point(x: 31, y: 76)
]
let smallestSet = cords.min(by: { $0.x < $1.x })!
let smallestCord = smallestSet.x
print("\(smallestCord) \(smallestSet.toArray())")

---

使用axis.x.rawValueThank，这非常有效！

struct Point {
    var x: Int
    var y: Int

    // For when you need to convert it to array to pass into other functions
    func toArray() -> [Int] {
        return [x, y]
    }
}

let cords = [
    Point(x: 10, y: 21),
    Point(x: 23, y: 11),
    Point(x: 42, y: 12),
    Point(x: 31, y: 76)
]
let smallestSet = cords.min(by: { $0.x < $1.x })!
let smallestCord = smallestSet.x
print("\(smallestCord) \(smallestSet.toArray())")