快速检查日期是今天还是明天答案

【问题标题】：swift check date is today or tomorrow快速检查日期是今天还是明天
【发布时间】：2021-11-28 21:50:26
【问题描述】：

我有一个整数数组，它是今天和明天日期的集合，我想根据日期的类型来分隔整数数组

let dateCollection = [
    1633722900,
    1633730500,
    1633754910,
    1633758913,
    1633820400,
    1633824000,
    1633827600,
    1633831200,
    1633834800,
    1633838400,
    1633842000
   ]

预期结果

let today: [Int] = [
    1633722900,
    1633730500,
    1633754910,
    1633758913
]

let tomorrow: [Int] = [  
    1633820400,
    1633824000,
    1633827600,
    1633831200,
    1633834800,
    1633838400,
    1633842000
]

我应该怎么做才能将它们分开，我已经做了一个扩展，将整数转换为日期，反之亦然，并将其显示为时间，我也已经创建了日期到时间的扩展

func getTimetringFromINT() -> String {
    let date = Date(timeIntervalSince1970: TimeInterval(self))
    let dateFormatter = DateFormatter()
    dateFormatter.locale = Locale(identifier: "id")
    dateFormatter.dateFormat = "HH:mm"
    return dateFormatter.string(from: date)
}

selector i made, after convert the date to Time string

【问题讨论】：

标签： arrays swift

【解决方案1】：

一种有效的方法是计算今天和明天之间午夜的 int 值，然后根据该值拆分数组

let calendar = Calendar.current
var today = [Int]()
var tomorrow = [Int]()
if let midnight = calendar.date(byAdding: .day, value: 1, to: calendar.startOfDay(for: .now))?.timeIntervalSince1970 {
    let limit = Int(midnight)
    dateCollection.forEach { $0 < limit ? today.append($0) : tomorrow.append($0) }
}

【讨论】：

【解决方案2】：

您可以使用Calendar.current.ordinality 比较各个日期的一年中的哪一天。下面是一个示例，它生成今天和明天的日期，然后将它们过滤回单独的数组：

let today = Date()
let todayInts = Array(0..<10).map { today.timeIntervalSince1970 + TimeInterval($0) }
print("Today:", todayInts,"\n")

let tomorrow = Calendar.current.date(byAdding: .day, value: 1, to: today)!
let tomorrowInts = Array(0..<10).map { tomorrow.timeIntervalSince1970 + TimeInterval($0) }
print("Tomorrow:", tomorrowInts,"\n")

let allInts = todayInts + tomorrowInts

let todayDayOfYear = Calendar.current.ordinality(of: .day, in: .year, for: today)!

let filteredTodayInts = allInts.filter { Calendar.current.ordinality(of: .day, in: .year, for: Date(timeIntervalSince1970: $0)) == todayDayOfYear }
print("Filtered today:", filteredTodayInts,"\n")

let tomorrowDayOfYear = todayDayOfYear + 1

let filteredTomorrowInts = allInts.filter { Calendar.current.ordinality(of: .day, in: .year, for: Date(timeIntervalSince1970: $0)) == tomorrowDayOfYear }
print("Filtered tomorrow:", filteredTomorrowInts,"\n")

【讨论】：

【解决方案3】：

另一种方法是使用Calendar API 和partition 数组获取第二天的开始日期（不管夏令时更改）

let startOfTomorrow = Calendar.current.nextDate(after: Date(), 
                                       matching: DateComponents(hour: 0), 
                                       matchingPolicy: .nextTime)!
                                      .timeIntervalSince1970
let splitIndex = dateCollection.partition{ $0 < Int(startOfTomorrow) }
let tomorrowDates = dateCollection[..<splitIndex]
let todayDates = dateCollection[splitIndex...]

为了能够运行此声明 dateCollection 为 var

【讨论】：

【解决方案4】：

通过获取任意时间的 StartOfDay，我们可以对共享相同 StartOfDay 的所有 Date 进行分类。

extension Date {
    var morning: Date { Calendar.current.startOfDay(for: self) }
    var nextMorning: Date { Calendar.current.date(byAdding: .day, value: 1, to: self)!.morning }
}
extension Int {
    var since1970: Date { Date(timeIntervalSince1970: TimeInterval(self)) }
}

在这种情况下：

let todayMorning    = Date().morning     // Date().advanced(by: 3600*24 * -19).morning
let tomorrowMorning = Date().nextMorning // Date().advanced(by: 3600*24 * -19).nextMorning

let dateCollection  = [ ... ]

let today    = dateCollection.filter{ $0.since1970.morning == todayMorning }
let tomorrow = dateCollection.filter{ $0.since1970.morning == tomorrowMorning }

【讨论】：

86400 math 强烈建议不要使用，因为夏令时更改的日子可能有82800 或90000