在给定的一天中获取每分钟的数组的最有效方法是什么？

Question

我正在尝试构建一个 [Date] 数组，它代表一天中的每一分钟。这是我想出的，但想知道是否有更有效的方法来实现这一点？

let calendar = Calendar.current

var arrayOfDaysMinutes: [Date] = []

var midnight = calendar.startOfDay(for: Date())

if let endOfDayDate = calendar.date(bySettingHour: 23, minute: 59, second: 59, of: midnight) {
    print("midnight = \(midnight) and one second before midnight = \(endOfDayDate)")
    
    for i in 0...1440 {
        print("i = \(i)")
        let nextMinute = midnight.addingTimeInterval(60 * Double(i))
        arrayOfDaysMinutes.append(nextMinute)
    }
    
    print("arrayOfDaysMinutes count = \(arrayOfDaysMinutes.count)")
    
    for minute in arrayOfDaysMinutes {
        print("minute = \(minute)")
    }
    
    
}

Answer 1

请注意，并非每一天都有 24 小时。它也可能有 23 或 25 个。关于最有效的方式，我认为使用 DateComponentes 日期属性比添加分钟或在日期之后获取下一个日期要快得多：

---

extension Date {
    func year(using calendar: Calendar = .current) ->  Int {
        calendar.component(.year, from: self)
    }
    func month(using calendar: Calendar = .current) ->  Int {
        calendar.component(.month, from: self)
    }
    func day(using calendar: Calendar = .current) ->  Int {
        calendar.component(.day, from: self)
    }
    func noon(using calendar: Calendar = .current) -> Date  {
        calendar.date(bySettingHour: 12, minute: 0, second: 0, of: self)!
    }
    func startOfDay(using calendar: Calendar = .current) -> Date {
        calendar.startOfDay(for: self)
    }
    func dayAfter(using calendar: Calendar = .current) -> Date {
        calendar.date(byAdding: .day, value: 1, to: noon(using: calendar))!
    }
    func startOfNextDay(using calendar: Calendar = .current) -> Date {
        calendar.startOfDay(for: dayAfter(using: calendar))
    }
}

---

let calendar = Calendar.current
let date = Date()
let startOfDay = date.startOfDay(using: calendar)
let startOfNextDay = startOfDay.startOfNextDay(using: calendar)
let minutes = calendar.dateComponents([.minute], from: startOfDay, to: startOfNextDay).minute!
let year = date.year(using: calendar)
let month = date.month(using: calendar)
let day = date.day(using: calendar)

let dates = (0..<minutes).compactMap {
    DateComponents(calendar: calendar, year: year, month: month, day: day, minute: $0).date
}
print("minutes count:", dates.count)  // "minutes count: 1440\n"

for minute in dates {
    print("minute = \(minute)")
}