我在Swift中有一个自定义的OptionSetType结构。如何枚举实例的所有值？
这是我的OptionSetType：
struct WeekdaySet: OptionSetType {
let rawValue: UInt8
init(rawValue: UInt8) {
self.rawValue = rawValue
}
static let Sunday = WeekdaySet(rawValue: 1 << 0)
static let Monday = WeekdaySet(rawValue: 1 << 1)
static let Tuesday = WeekdaySet(rawValue: 1 << 2)
static let Wednesday = WeekdaySet(rawValue: 1 << 3)
static let Thursday = WeekdaySet(rawValue: 1 << 4)
static let Friday = WeekdaySet(rawValue: 1 << 5)
static let Saturday = WeekdaySet(rawValue: 1 << 6)
}
我想要这样的东西：
let weekdays: WeekdaySet = [.Monday,.Tuesday]
for weekday in weekdays {
// Do something with weekday
}
在Swift 3中，标准库中没有方法
枚举一个OptionSetType(Swift 2)的元素。
OptionSet(Swift 3)。
原文链接：https://www.f2er.com/swift/320326.html枚举一个OptionSetType(Swift 2)的元素。
OptionSet(Swift 3)。
这是一个简单地检查每一位的可能的实现
的基本原始值，并且对于设置的每个位，
返回相应的元素。
“溢出乘法”& * 2用作左移，因为<仅针对具体的整数类型定义，但不适用于IntegerType协议。 Swift 2.2：
public extension OptionSetType where RawValue : IntegerType {
func elements() -> AnySequence<Self> {
var remainingBits = self.rawValue
var bitMask: RawValue = 1
return AnySequence {
return AnyGenerator {
while remainingBits != 0 {
defer { bitMask = bitMask &* 2 }
if remainingBits & bitMask != 0 {
remainingBits = remainingBits & ~bitMask
return Self(rawValue: bitMask)
}
}
return nil
}
}
}
}
使用示例
let weekdays: WeekdaySet = [.Monday,.Tuesday]
for weekday in weekdays.elements() {
print(weekday)
}
// Output:
// WeekdaySet(rawValue: 2)
// WeekdaySet(rawValue: 4)
Swift 3：
public extension OptionSet where RawValue : Integer {
func elements() -> AnySequence<Self> {
var remainingBits = rawValue
var bitMask: RawValue = 1
return AnySequence {
return AnyIterator {
while remainingBits != 0 {
defer { bitMask = bitMask &* 2 }
if remainingBits & bitMask != 0 {
remainingBits = remainingBits & ~bitMask
return Self(rawValue: bitMask)
}
}
return nil
}
}
}
}
