两个NSDates之间的快速日子

Question

我想知道是否有一些新的和令人敬畏的可能性来获得Swift /＆＃34; new＆＃34;中两个NSDates之间的天数。可可？

E.g。就像在Ruby中我会这样做：

(end_date - start_date).to_i

Answer 1

接受的答案不会在两个日期之间返回正确的日期号码。你也必须考虑时差。例如，如果您比较日期2015-01-01 10:00和2015-01-02 09:00，则这些日期之间的天数将返回0（零），因为这些日期之间的差异小于24小时（它的23小时）

如果你的目的是获得两个日期之间的确切日期，你可以像这样解决这个问题：

// 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

以下是我对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的答案，所以我将添加自己的答案：

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

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

Answer 4

我翻译了Objective-C answer

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

最难的部分是自动填充功能坚持fromDate和toDate将NSDate?，但实际上它们必须是NSDate!，如参考中所示。

我没有看到运算符的良好解决方案如何，因为您希望在每种情况下以不同方式指定单位。你可以返回时间间隔，但不会获得太多。

Answer 5

这是一个非常好的Date扩展程序，用于在日期，月，日，小时，分钟，秒之间获得差异

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 6

Swift 3 iOS 10 Beta 4的更新

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

以下是Swift 3（针对IOS 10 Beta测试）的答案

python  x.py,

然后你就可以这样称呼它

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

Answer 8

Swift 3.感谢上面的Emin Buğra Saral 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

Answer 9

swift内置的东西仍然非常基础。因为他们应该处于这个早期阶段。但是你可以添加自己的东西，带来重载运算符和全局域函数带来的风险。它们将在您的模块本地。

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 10

以下是我对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 11

几乎没有任何特定于Swift的标准库;只是精简的基本数字，字符串和集合类型。

完全可以使用扩展来定义这样的shorthands，但就实际开箱即用的API而言，没有“新的”Cocoa; Swift只是直接映射到已经存在的旧的详细Cocoa API。

Answer 12

艾琳的方法更新为Swift 3，显示从今天开始的日子（无视时间）

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 13

即使这个帖子已经有一年了，我也要添加我的版本。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."

我希望它有所帮助。

干杯，

Answer 14

这是Emin针对Swift 5的答案的更新版本，其中包含了建议使用中午而不是午夜作为比较天数的确定时间。它还通过返回一个可选值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 15

Swift 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 16

所有答案都很好。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 17

这将返回某些Date与今天之间的绝对天数：

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

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 19

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

然后像使用它

    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 20

更简单的选择是在日期

上创建扩展程序

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 21

  

雨燕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 22

一个方便的内衬：

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

Answer 23

/**
 * Populate hidden input with ACF values
 */
function nf_hidden_field_values( $value, $field_type, $field_settings ) {
    global $post;

    if ( $field_settings['key'] == 'hidden_field_1' ) {
        return get_field('acf_field_1', $post->ID);
    }

    if ( $field_settings['key'] == 'hidden_field_2' ) {
        return get_field('acf_field_2', $post->ID);
    }

    return $value;
}
add_filter( 'ninja_forms_render_default_value', 'nf_hidden_field_values', 10, 3 );

如果您需要年月日和小时作为字符串使用此

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

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

Answer 24

斯威夫特3天 - 从今天到日期

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 25

2017版，复制并粘贴

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 26

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

Answer 27

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