两个 NSDate 之间的快速日子

Question

我想知道是否有一些新的和很棒的可能性可以在 Swift /“新”可可中获得两个 NSDate 之间的天数？

例如，像在 Ruby 中我会这样做：

(end_date - start_date).to_i

Answer 1

您还必须考虑时差。 例如，如果您比较日期2015-01-01 10:00和2015-01-02 09:00 ，这些日期之间的天数将返回为 0（零），因为这些日期之间的差异小于 24 小时（即 23小时）。

如果您的目的是获取两个日期之间的确切天数，您可以像这样解决此问题：

// Assuming that firstDate and secondDate are defined
// ...

let calendar = NSCalendar.currentCalendar()

// Replace the hour (time) of both dates with 00:00
let date1 = calendar.startOfDayForDate(firstDate)
let date2 = calendar.startOfDayForDate(secondDate)

let flags = NSCalendarUnit.Day
let components = calendar.components(flags, fromDate: date1, toDate: date2, options: [])

components.day  // This will return the number of day(s) between dates

Swift 3 和 Swift 4 版本

let calendar = Calendar.current

// Replace the hour (time) of both dates with 00:00
let date1 = calendar.startOfDay(for: firstDate)
let date2 = calendar.startOfDay(for: secondDate)

let components = calendar.dateComponents([.day], from: date1, to: date2)

Answer 2

这是我对 Swift 2 的回答：

func daysBetweenDates(startDate: NSDate, endDate: NSDate) -> Int
{
    let calendar = NSCalendar.currentCalendar()

    let components = calendar.components([.Day], fromDate: startDate, toDate: endDate, options: [])

    return components.day
}

Answer 3

我看到了几个 Swift3 答案，所以我会添加自己的：

public static func daysBetween(start: Date, end: Date) -> Int {
   Calendar.current.dateComponents([.day], from: start, to: end).day!
}

命名感觉更 Swifty，它是一行，并使用最新的dateComponents()方法。

Answer 4

这是非常好的， Date扩展以获取年、月、日、小时、分钟、秒的日期之间的差异

extension Date {

    func years(sinceDate: Date) -> Int? {
        return Calendar.current.dateComponents([.year], from: sinceDate, to: self).year
    }

    func months(sinceDate: Date) -> Int? {
        return Calendar.current.dateComponents([.month], from: sinceDate, to: self).month
    }

    func days(sinceDate: Date) -> Int? {
        return Calendar.current.dateComponents([.day], from: sinceDate, to: self).day
    }

    func hours(sinceDate: Date) -> Int? {
        return Calendar.current.dateComponents([.hour], from: sinceDate, to: self).hour
    }

    func minutes(sinceDate: Date) -> Int? {
        return Calendar.current.dateComponents([.minute], from: sinceDate, to: self).minute
    }

    func seconds(sinceDate: Date) -> Int? {
        return Calendar.current.dateComponents([.second], from: sinceDate, to: self).second
    }

}

Answer 5

我翻译了我的Objective-C 答案

let start = "2010-09-01"
let end = "2010-09-05"

let dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd"

let startDate:NSDate = dateFormatter.dateFromString(start)
let endDate:NSDate = dateFormatter.dateFromString(end)

let cal = NSCalendar.currentCalendar()


let unit:NSCalendarUnit = .Day

let components = cal.components(unit, fromDate: startDate, toDate: endDate, options: nil)


println(components)

结果

<NSDateComponents: 0x10280a8a0>
     Day: 4

最困难的部分是自动完成坚持 fromDate 和 toDate 将是NSDate? ，但确实它们必须是NSDate! 如参考资料所示。

我看不出一个好的操作员解决方案是什么样的，因为您想在每种情况下以不同的方式指定单位。 您可以返回时间间隔，但不会获得太多收益。

Answer 6

Swift 3 iOS 10 Beta 4 更新

func daysBetweenDates(startDate: Date, endDate: Date) -> Int {
    let calendar = Calendar.current
    let components = calendar.dateComponents([Calendar.Component.day], from: startDate, to: endDate)
    return components.day!
}

Answer 7

Swift 5. 感谢上面的Emin Buğra Saral提出的startOfDay建议。

extension Date {
    
    func daysBetween(date: Date) -> Int {
        return Date.daysBetween(start: self, end: date)
    }
    
    static func daysBetween(start: Date, end: Date) -> Int {
        let calendar = Calendar.current
        
        // Replace the hour (time) of both dates with 00:00
        let date1 = calendar.startOfDay(for: start)
        let date2 = calendar.startOfDay(for: end)
        
        let a = calendar.dateComponents([.day], from: date1, to: date2)
        return a.value(for: .day)!
    }
}

用法：

let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd"
let start = dateFormatter.date(from: "2017-01-01")!
let end = dateFormatter.date(from: "2018-01-01")!

let diff = Date.daysBetween(start: start, end: end) // 365
// or
let diff = start.daysBetween(date: end) // 365

Answer 8

这是 Swift 3 的答案（针对 IOS 10 Beta 测试）

func daysBetweenDates(startDate: Date, endDate: Date) -> Int
{
    let calendar = Calendar.current
    let components = calendar.components([.day], from: startDate, to: endDate, options: [])
    return components.day!
}

然后你可以这样称呼它

let pickedDate: Date = sender.date
let NumOfDays: Int = daysBetweenDates(startDate: pickedDate, endDate: Date())
    print("Num of Days: \(NumOfDays)")

Answer 9

斯威夫特 5

工作，你需要将两天的时间设置为相同，如果你是秒就错了

func daysBetween(start: Date, end: Date) -> Int {
    let start = Calendar.current.date(bySettingHour: 0, minute: 0, second: 0, of: start)!
    let end = Calendar.current.date(bySettingHour: 0, minute: 0, second: 0, of: end)!
    return Calendar.current.dateComponents([.day], from: start, to: end).day ?? 0
}

Answer 10

swift内置的东西还是很基础的。 因为他们应该处于这个早期阶段。 但是您可以添加自己的东西，但会带来重载运算符和全局域函数的风险。 不过，它们将在您的模块中本地。

let now = NSDate()
let seventies = NSDate(timeIntervalSince1970: 0)

// Standard solution still works
let days = NSCalendar.currentCalendar().components(.CalendarUnitDay, 
           fromDate: seventies, toDate: now, options: nil).day

// Flashy swift... maybe...
func -(lhs:NSDate, rhs:NSDate) -> DateRange {
    return DateRange(startDate: rhs, endDate: lhs)
}

class DateRange {
    let startDate:NSDate
    let endDate:NSDate
    var calendar = NSCalendar.currentCalendar()
    var days: Int {
        return calendar.components(.CalendarUnitDay, 
               fromDate: startDate, toDate: endDate, options: nil).day
    }
    var months: Int {
        return calendar.components(.CalendarUnitMonth, 
               fromDate: startDate, toDate: endDate, options: nil).month
    }
    init(startDate:NSDate, endDate:NSDate) {
        self.startDate = startDate
        self.endDate = endDate
    }
}

// Now you can do this...
(now - seventies).months
(now - seventies).days

Answer 11

这是 Emin 对 Swift 5 的回答的更新版本，其中包含使用中午而不是午夜作为比较天数的最终时间的建议。 它还通过返回一个可选项来处理各种日期函数的潜在故障。

///
/// This is an approximation; it does not account for time differences. It will set the time to 1200 (noon) and provide the absolute number
/// of days between now and the given date. If the result is negative, it should be read as "days ago" instead of "days from today."
/// Returns nil if something goes wrong initializing or adjusting dates.
///

func daysFromToday() -> Int?
{
    let calendar = NSCalendar.current

    // Replace the hour (time) of both dates with noon. (Noon is less likely to be affected by DST changes, timezones, etc. than midnight.)
    guard let date1 = calendar.date(bySettingHour: 12, minute: 00, second: 00, of: calendar.startOfDay(for: Date())),
          let date2 = calendar.date(bySettingHour: 12, minute: 00, second: 00, of: calendar.startOfDay(for: self)) else
    {
        return nil
    }
    
    return calendar.dateComponents([.day], from: date1, to: date2).day
}

Answer 12

这是我对 Swift 3 的回答：

func daysBetweenDates(startDate: NSDate, endDate: NSDate, inTimeZone timeZone: TimeZone? = nil) -> Int {
    var calendar = Calendar.current
    if let timeZone = timeZone {
        calendar.timeZone = timeZone
    }
    let dateComponents = calendar.dateComponents([.day], from: startDate.startOfDay, to: endDate.startOfDay)
    return dateComponents.day!
}

Answer 13

您可以使用以下扩展名：

public extension Date {
    func daysTo(_ date: Date) -> Int? {
        let calendar = Calendar.current

        // Replace the hour (time) of both dates with 00:00
        let date1 = calendar.startOfDay(for: self)
        let date2 = calendar.startOfDay(for: date)

        let components = calendar.dateComponents([.day], from: date1, to: date2)
        return components.day  // This will return the number of day(s) between dates
    }
}

然后，您可以这样称呼它：

startDate.daysTo(endDate)

Answer 14

目前几乎没有任何 Swift 特定的标准库。 只是精益的基本数字、字符串和集合类型。

使用扩展来定义这样的简写是完全可能的，但就实际开箱即用的 API 而言，没有“新”的 Cocoa。 Swift 只是直接映射到旧的冗长 Cocoa API，因为它们已经存在。

Answer 15

即使这个线程已经有一年了，我也会添加我的版本。 我的代码如下所示：

    var name = txtName.stringValue // Get the users name

    // Get the date components from the window controls
    var dateComponents = NSDateComponents()
    dateComponents.day = txtDOBDay.integerValue
    dateComponents.month = txtDOBMonth.integerValue
    dateComponents.year = txtDOBYear.integerValue

    // Make a Gregorian calendar
    let calendar = NSCalendar(identifier: NSCalendarIdentifierGregorian)

    // Get the two dates we need
    var birthdate = calendar?.dateFromComponents(dateComponents)
    let currentDate = NSDate()

    var durationDateComponents = calendar?.components(NSCalendarUnit.CalendarUnitDay, fromDate: birthdate!, toDate: currentDate, options: nil)

    let numberOfDaysAlive = durationDateComponents?.day

    println("\(numberOfDaysAlive!)")

    txtGreeting.stringValue = "Hello \(name), You have been alive for \(numberOfDaysAlive!) days."

我希望它可以帮助某人。

干杯，

Answer 16

Erin 的方法更新为 Swift 3，显示从今天开始的天数（不考虑一天中的时间）

func daysBetweenDates( endDate: Date) -> Int 
    let calendar: Calendar = Calendar.current 
    let date1 = calendar.startOfDay(for: Date()) 
    let date2 = calendar.startOfDay(for: secondDate) 
    return calendar.dateComponents([.day], from: date1, to: date2).day! 
}

Answer 17

这将返回某个Date和今天之间的天数绝对差：

extension Date {
  func daysFromToday() -> Int {
    return abs(Calendar.current.dateComponents([.day], from: self, to: Date()).day!)
  }
}

然后使用它：

if someDate.daysFromToday() >= 7 {
  // at least a week from today
}

Answer 18

更简单的选择是在 Date 创建一个扩展

public extension Date {

        public var currentCalendar: Calendar {
            return Calendar.autoupdatingCurrent
        }

        public func daysBetween(_ date: Date) -> Int {
            let components = currentCalendar.dateComponents([.day], from: self, to: date)
            return components.day!
        }
    }

Answer 19

斯威夫特 3.2

extension DateComponentsFormatter {
    func difference(from fromDate: Date, to toDate: Date) -> String? {
        self.allowedUnits = [.year,.month,.weekOfMonth,.day]
        self.maximumUnitCount = 1
        self.unitsStyle = .full
        return self.string(from: fromDate, to: toDate)
    }
}

Answer 20

所有的答案都很好。 但是对于本地化，我们需要计算两个日期之间的小数天数。 所以我们可以提供可持续的十进制格式。

// This method returns the fractional number of days between to dates
func getFractionalDaysBetweenDates(date1: Date, date2: Date) -> Double {

    let components = Calendar.current.dateComponents([.day, .hour], from: date1, to: date2)

    var decimalDays = Double(components.day!)
    decimalDays += Double(components.hour!) / 24.0

    return decimalDays
}

Answer 21

好方便的一个衬里：

extension Date {
  var daysFromNow: Int {
    return Calendar.current.dateComponents([.day], from: Date(), to: self).day!
  }
}

Answer 22

Swift 3 - 从今天到今天的天数

func daysUntilDate(endDateComponents: DateComponents) -> Int
    {
        let cal = Calendar.current
        var components = cal.dateComponents([.era, .year, .month, .day], from: NSDate() as Date)
        let today = cal.date(from: components)
        let otherDate = cal.date(from: endDateComponents)

        components = cal.dateComponents([Calendar.Component.day], from: (today! as Date), to: otherDate!)
        return components.day!
    }

像这样调用函数

// Days from today until date
   var examnDate = DateComponents()
   examnDate.year = 2016
   examnDate.month = 12
   examnDate.day = 15
   let daysCount = daysUntilDate(endDateComponents: examnDate)

Answer 23

  func completeOffset(from date:Date) -> String? {

    let formatter = DateComponentsFormatter()
    formatter.unitsStyle = .brief

    return  formatter.string(from: Calendar.current.dateComponents([.year,.month,.day,.hour,.minute,.second], from: date, to: self))




}

如果您需要年月日和小时作为字符串，请使用此

var 明天 = Calendar.current.date(byAdding: .day, value: 1, to: Date())！

让 dc = tomorrow.completeOffset(from: Date())

Answer 24

斯威夫特4

 func getDateHeader(indexPath: Int) -> String {
    let formatter2 = DateFormatter()
    formatter2.dateFormat = "MM-dd-yyyy"
    var dateDeadline : Date?

    dateDeadline = formatter2.date(from: arrCompletedDate[indexPath] as! String)

    let currentTime = dateDeadline?.unixTimestamp
    let calendar = NSCalendar.current

    let date = NSDate(timeIntervalSince1970: Double(currentTime!))
    if calendar.isDateInYesterday(date as Date) { return "Yesterday" }
    else if calendar.isDateInToday(date as Date) { return "Today" }
    else if calendar.isDateInTomorrow(date as Date) { return "Tomorrow" }
    else {
        let startOfNow = calendar.startOfDay(for: NSDate() as Date)
        let startOfTimeStamp = calendar.startOfDay(for: date as Date)
        let components = calendar.dateComponents([.day], from: startOfNow, to: startOfTimeStamp)
        let day = components.day!
        if day < 1 { return "\(abs(day)) days ago" }
        else { return "In \(day) days" }
    }
}

Answer 25

extension Date {
    func daysFromToday() -> Int {
        return Calendar.current.dateComponents([.day], from: self, to: Date()).day!
    }
}

然后像这样使用它

    func dayCount(dateString: String) -> String{
        let dateFormatter = DateFormatter()
        dateFormatter.dateFormat = "MMM dd,yyyy hh:mm a"
        let fetchedDate = dateFormatter.date(from: dateString)


        let day = fetchedDate?.daysFromToday()
        if day! > -1{
            return "\(day!) days passed."
        }else{
        return "\(day! * -1) days left."
        }
    }

Answer 26

extension Date {
static func - (recent: Date, previous: Date) -> DateComponents {
    var dateComponents = DateComponents()
    dateComponents.year = Calendar.current.dateComponents([.day], from: previous, to: recent).year
    dateComponents.month = Calendar.current.dateComponents([.month], from: previous, to: recent).month
    dateComponents.day = Calendar.current.dateComponents([.day], from: previous, to: recent).day
    dateComponents.hour = Calendar.current.dateComponents([.hour], from: previous, to: recent).hour
    dateComponents.minute = Calendar.current.dateComponents([.minute], from: previous, to: recent).minute
    dateComponents.second = Calendar.current.dateComponents([.second], from: previous, to: recent).second
    return dateComponents
   }
}

Answer 27

2017版，复制粘贴

func simpleIndex(ofDate: Date) -> Int {
    
    // index here just means today 0, yesterday -1, tomorrow 1 etc.
    
    let c = Calendar.current
    let todayRightNow = Date()
    
    let d = c.date(bySetting: .hour, value: 13, of: ofDate)
    let t = c.date(bySetting: .hour, value: 13, of: todayRightNow)
    
    if d == nil || today == nil {
    
        print("weird problem simpleIndex#ofDate")
        return 0
    }
    
    let r = c.dateComponents([.day], from: today!, to: d!)
    // yesterday is negative one, tomorrow is one
    
    if let o = r.value(for: .day) {
        
        return o
    }
    else {
    
        print("another weird problem simpleIndex#ofDate")
        return 0
    }
}

Answer 28

let calendar = NSCalendar.currentCalendar();
let component1 = calendar.component(.Day, fromDate: fromDate)
let component2 = calendar.component(.Day, fromDate: toDate)
let difference  = component1 - component2

Answer 29

Swift 5.2.4 解决方案：

import UIKit

let calendar = Calendar.current

let start = "2010-09-01"
let end = "2010-09-05"

let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd"

let firstDate = dateFormatter.date(from: start)!
let secondDate = dateFormatter.date(from: end)!

// Replace the hour (time) of both dates with 00:00
let date1 = calendar.startOfDay(for: firstDate)
let date2 = calendar.startOfDay(for: secondDate)

let components = calendar.dateComponents([Calendar.Component.day], from: date1, to: date2)

components.day  // This will return the number of day(s) between dates