swift – 使用原始值进行枚举

发布时间：2020-12-14 05:46:51 所属栏目：百科来源：网络整理

导读：为什么我不能用这样的原始值定义枚举？ enum Edges : (Double,Double) { case TopLeft = (0.0,0.0) case TopRight = (1.0,0.0) case BottomLeft = (0.0,1.0) case BottomRight = (1.0,1.0)} Because： Raw values can be strings,characters,or any of the i

为什么我不能用这样的原始值定义枚举？

enum Edges : (Double,Double) {
    case TopLeft = (0.0,0.0)
    case TopRight = (1.0,0.0)
    case BottomLeft = (0.0,1.0)
    case BottomRight = (1.0,1.0)
}

Because：

Raw values can be strings,characters,or any of the integer or floating-point number types.

但是有一个替代解决方案：

enum Edges {
    case TopLeft
    case TopRight
    case BottomLeft
    case BottomRight

    func getTuple() -> (Double,Double) {
        switch self {
        case .TopLeft:
            return (0.0,0.0)
        case .TopRight:
            return (1.0,0.0)
        case .BottomLeft:
            return (0.0,1.0)
        case .BottomRight:
            return (1.0,1.0)
        }
    }
}

let a = Edges.BottomLeft
a.getTuple() // returning (0,1)

（编辑：李大同）

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