关联值设置枚举
enum Trade {
case Buy(stock: String, amount: Int)
case Sell(stock: String, amount: Int)
}
模式匹配访问
let trade = Trade.Buy(stock: "APPL", amount: 500)
//值绑定模式
switch trade {
case .Buy(stock: let name, amount: let count):
print("\(name)--\(count)")
default:
break
}
//当只有一个条件的时候,用switch会显得冗余,直接用if case let会使代码读起来更便捷
if case let Trade.Buy(stock, amount) = trade {
print("buy \(amount) of \(stock)")
}