如何在 swift 中获取本周星期一的日期
How to get Monday's date of the current week in swift
我正在尝试获取本周星期一的日期。在我的 table 视图中，这被视为一周的第一天。
我还需要获取本周的星期日。在我的 table 视图中，这被视为一周的最后一天。
当前尝试：
let date = NSDate()
let calendar = NSCalendar.currentCalendar()
calendar.firstWeekday = 1
//attempt to changefirstday
let dateFormatter = NSDateFormatter()
let theDateFormat = NSDateFormatterStyle.ShortStyle
let theTimeFormat = NSDateFormatterStyle.ShortStyle
dateFormatter.dateStyle = theDateFormat
dateFormatter.timeStyle = theTimeFormat
let currentDateComponents = calendar.components([.YearForWeekOfYear, .WeekOfYear ], fromDate: date)
let startOfWeek = calendar.dateFromComponents(currentDateComponents)
print("startOfWeek is \(startOfWeek)")
let stringDate = dateFormatter.stringFromDate(startOfWeek!)
print("string date is \(stringDate)") //This is returning Sunday's date
尝试使用：
calendar.firstWeekday = 2
编辑
更具体地说：NSCalendar.currentCalendar() returns 用户日历。根据文档：
The returned calendar is formed from the settings for the current user’s chosen system locale overlaid with any custom settings the user has specified in System Preferences.
如果您希望始终将星期一作为第一天，我认为您应该使用：
let calendar = NSCalendar(calendarIdentifier: NSCalendarIdentifierGregorian)!
calendar!.firstWeekday = 2
我写了日期扩展来获取某个工作日的日期，下面是使用 Swift 5，
是多么容易
Date.today() // Oct 15, 2019 at 9:21 AM
Date.today().next(.monday) // Oct 21, 2019 at 9:21 AM
Date.today().next(.sunday) // Oct 20, 2019 at 9:21 AM
Date.today().previous(.sunday) // Oct 13, 2019 at 9:21 AM
Date.today().previous(.monday) // Oct 14, 2019 at 9:21 AM
Date.today().previous(.thursday) // Oct 10, 2019 at 9:21 AM
Date.today().next(.thursday) // Oct 17, 2019 at 9:21 AM
Date.today().previous(.thursday,
considerToday: true) // Oct 10, 2019 at 9:21 AM
Date.today().next(.monday)
.next(.sunday)
.next(.thursday) // Oct 31, 2019 at 9:21 AM
这里是日期扩展，
extension Date {
static func today() -> Date {
return Date()
}
func next(_ weekday: Weekday, considerToday: Bool = false) -> Date {
return get(.next,
weekday,
considerToday: considerToday)
}
func previous(_ weekday: Weekday, considerToday: Bool = false) -> Date {
return get(.previous,
weekday,
considerToday: considerToday)
}
func get(_ direction: SearchDirection,
_ weekDay: Weekday,
considerToday consider: Bool = false) -> Date {
let dayName = weekDay.rawValue
let weekdaysName = getWeekDaysInEnglish().map { [=11=].lowercased() }
assert(weekdaysName.contains(dayName), "weekday symbol should be in form \(weekdaysName)")
let searchWeekdayIndex = weekdaysName.firstIndex(of: dayName)! + 1
let calendar = Calendar(identifier: .gregorian)
if consider && calendar.component(.weekday, from: self) == searchWeekdayIndex {
return self
}
var nextDateComponent = calendar.dateComponents([.hour, .minute, .second], from: self)
nextDateComponent.weekday = searchWeekdayIndex
let date = calendar.nextDate(after: self,
matching: nextDateComponent,
matchingPolicy: .nextTime,
direction: direction.calendarSearchDirection)
return date!
}
}
// MARK: Helper methods
extension Date {
func getWeekDaysInEnglish() -> [String] {
var calendar = Calendar(identifier: .gregorian)
calendar.locale = Locale(identifier: "en_US_POSIX")
return calendar.weekdaySymbols
}
enum Weekday: String {
case monday, tuesday, wednesday, thursday, friday, saturday, sunday
}
enum SearchDirection {
case next
case previous
var calendarSearchDirection: Calendar.SearchDirection {
switch self {
case .next:
return .forward
case .previous:
return .backward
}
}
}
}
您可以使用日历 ISO8601，其中第一个工作日是星期一：
Swift 5.2 或更高版本
extension Calendar {
static let iso8601 = Calendar(identifier: .iso8601)
static let iso8601UTC: Calendar = {
var calendar = Calendar(identifier: .iso8601)
calendar.timeZone = TimeZone(identifier: "UTC")!
return calendar
}()
}
let monday =
Calendar.iso8601.dateComponents([.calendar, .yearForWeekOfYear, .weekOfYear], from: Date()).date! // "Nov 9, 2020 at 12:00 AM"
print(monday.description(with: .current)) // "Monday, November 9, 2020 at 12:00:00 AM Brasilia Standard Time\n"
let mondayUTC =
Calendar.iso8601UTC.dateComponents([.calendar, .yearForWeekOfYear, .weekOfYear], from: Date()).date! // "Nov 8, 2020 at 9:00 PM" TimeZone -03:00
print(mondayUTC) // "2020-11-09 00:00:00 +0000\n"
作为 Date 计算机实施 属性 扩展名：
extension Date {
var mondayOfTheSameWeek: Date {
Calendar.iso8601.dateComponents([.calendar, .yearForWeekOfYear, .weekOfYear], from: self).date!
}
var mondayOfTheSameWeekAtUTC: Date {
Calendar.iso8601UTC.dateComponents([.calendar, .yearForWeekOfYear, .weekOfYear], from: self).date!
}
}
let mondayOfTheSameWeek = Date().mondayOfTheSameWeek // "Nov 9, 2020 at 12:00 AM"
print(mondayOfTheSameWeek.description(with: .current)) // "Monday, November 9, 2020 at 12:00:00 AM Brasilia Standard Time\n"
let mondayOfTheSameWeekAtUTC = Date().mondayOfTheSameWeekAtUTC // "Nov 8, 2020 at 9:00 PM"
print(mondayOfTheSameWeekAtUTC) // "2020-11-09 00:00:00 +0000\n"
@Saneep 回答的补充
如果您想根据 given/current 日期获得准确的日期时间（假设您想将星期一的日期时间 -> 23-05-2016 12:00:00 转换为 23-05-2016 05:35:17），那么试试这个：
func convertDate(date: NSDate, toGivendate: NSDate) -> NSDate {
let calendar = NSCalendar.currentCalendar()
let comp = calendar.components([.Year, .Month, .Day, .Hour, .Minute, .Second], fromDate: toGivendate)
let hour = comp.hour
let minute = comp.minute
let second = comp.second
let dateComp = calendar.components([.Year, .Month, .Day], fromDate: date)
let year = dateComp.year
let month = dateComp.month
let day = dateComp.day
let components = NSDateComponents()
components.year = year
components.month = month
components.day = day
components.hour = hour
components.minute = minute
components.second = second
let newConvertedDate = calendar.dateFromComponents(components)
return newConvertedDate!
}
这是我创建的扩展程序，首先找到星期日然后添加一天
extension Date {
var startOfWeek: Date? {
let gregorian = Calendar(identifier: .gregorian)
guard let sunday = gregorian.date(from: gregorian.dateComponents([.yearForWeekOfYear, .weekOfYear], from: self)) else { return nil }
return gregorian.date(byAdding: .day, value: 1, to: sunday)
}
}
这是 的简化版本。
用法：
Date().next(.monday)
Date().next(.monday, considerToday: true)
Date().next(.monday, direction: .backward)
分机：
public func next(_ weekday: Weekday,
direction: Calendar.SearchDirection = .forward,
considerToday: Bool = false) -> Date
{
let calendar = Calendar(identifier: .gregorian)
let components = DateComponents(weekday: weekday.rawValue)
if considerToday &&
calendar.component(.weekday, from: self) == weekday.rawValue
{
return self
}
return calendar.nextDate(after: self,
matching: components,
matchingPolicy: .nextTime,
direction: direction)!
}
public enum Weekday: Int {
case sunday = 1, monday, tuesday, wednesday, thursday, friday, saturday
}
Swift 4 解
我已经根据我的要求弄清楚了，在那里我找到了关注的日期。
1. Today
2. Tomorrow
3. This Week
4. This Weekend
5. Next Week
6. Next Weekend
所以，我创建了 Date Extension 来获取 本周 和 下周 的日期。
代码
extension Date {
func getWeekDates() -> (thisWeek:[Date],nextWeek:[Date]) {
var tuple: (thisWeek:[Date],nextWeek:[Date])
var arrThisWeek: [Date] = []
for i in 0..<7 {
arrThisWeek.append(Calendar.current.date(byAdding: .day, value: i, to: startOfWeek)!)
}
var arrNextWeek: [Date] = []
for i in 1...7 {
arrNextWeek.append(Calendar.current.date(byAdding: .day, value: i, to: arrThisWeek.last!)!)
}
tuple = (thisWeek: arrThisWeek,nextWeek: arrNextWeek)
return tuple
}
var tomorrow: Date {
return Calendar.current.date(byAdding: .day, value: 1, to: noon)!
}
var noon: Date {
return Calendar.current.date(bySettingHour: 12, minute: 0, second: 0, of: self)!
}
var startOfWeek: Date {
let gregorian = Calendar(identifier: .gregorian)
let sunday = gregorian.date(from: gregorian.dateComponents([.yearForWeekOfYear, .weekOfYear], from: self))
return gregorian.date(byAdding: .day, value: 1, to: sunday!)!
}
func toDate(format: String) -> String {
let formatter = DateFormatter()
formatter.dateFormat = format
return formatter.string(from: self)
}
}
用法：
let arrWeekDates = Date().getWeekDates() // Get dates of Current and Next week.
let dateFormat = "MMM dd" // Date format
let thisMon = arrWeekDates.thisWeek.first!.toDate(format: dateFormat)
let thisSat = arrWeekDates.thisWeek[arrWeekDates.thisWeek.count - 2].toDate(format: dateFormat)
let thisSun = arrWeekDates.thisWeek[arrWeekDates.thisWeek.count - 1].toDate(format: dateFormat)
let nextMon = arrWeekDates.nextWeek.first!.toDate(format: dateFormat)
let nextSat = arrWeekDates.nextWeek[arrWeekDates.nextWeek.count - 2].toDate(format: dateFormat)
let nextSun = arrWeekDates.nextWeek[arrWeekDates.nextWeek.count - 1].toDate(format: dateFormat)
print("Today: \(Date().toDate(format: dateFormat))") // Sep 26
print("Tomorrow: \(Date().tomorrow.toDate(format: dateFormat))") // Sep 27
print("This Week: \(thisMon) - \(thisSun)") // Sep 24 - Sep 30
print("This Weekend: \(thisSat) - \(thisSun)") // Sep 29 - Sep 30
print("Next Week: \(nextMon) - \(nextSun)") // Oct 01 - Oct 07
print("Next Weekend: \(nextSat) - \(nextSun)") // Oct 06 - Oct 07
您可以根据需要修改Extension。
谢谢！
简单代码（记住要更好地照顾可选项）：
let now = Date()
var calendar = Calendar(identifier: .gregorian)
let timeZone = TimeZone(identifier: "UTC")!
let desiredWeekDay = 2
let weekDay = calendar.component(.weekday, from: now)
var weekDayDate = calendar.date(bySetting: .weekday, value: desiredWeekDay, of: now)!
/// Swift will give back the closest day matching the value above so we need to manipulate it to be always included at cuurent week.
if weekDayDate > now, weekDay > desiredWeekDay {
weekDayDate = weekDayDate - 7*24*60*60
}
print(weekDayDate)
我正在尝试获取本周星期一的日期。在我的 table 视图中，这被视为一周的第一天。 我还需要获取本周的星期日。在我的 table 视图中，这被视为一周的最后一天。
当前尝试：
let date = NSDate()
let calendar = NSCalendar.currentCalendar()
calendar.firstWeekday = 1
//attempt to changefirstday
let dateFormatter = NSDateFormatter()
let theDateFormat = NSDateFormatterStyle.ShortStyle
let theTimeFormat = NSDateFormatterStyle.ShortStyle
dateFormatter.dateStyle = theDateFormat
dateFormatter.timeStyle = theTimeFormat
let currentDateComponents = calendar.components([.YearForWeekOfYear, .WeekOfYear ], fromDate: date)
let startOfWeek = calendar.dateFromComponents(currentDateComponents)
print("startOfWeek is \(startOfWeek)")
let stringDate = dateFormatter.stringFromDate(startOfWeek!)
print("string date is \(stringDate)") //This is returning Sunday's date
尝试使用：
calendar.firstWeekday = 2
编辑
更具体地说：NSCalendar.currentCalendar() returns 用户日历。根据文档：
The returned calendar is formed from the settings for the current user’s chosen system locale overlaid with any custom settings the user has specified in System Preferences.
如果您希望始终将星期一作为第一天，我认为您应该使用：
let calendar = NSCalendar(calendarIdentifier: NSCalendarIdentifierGregorian)!
calendar!.firstWeekday = 2
我写了日期扩展来获取某个工作日的日期，下面是使用 Swift 5，
是多么容易Date.today() // Oct 15, 2019 at 9:21 AM
Date.today().next(.monday) // Oct 21, 2019 at 9:21 AM
Date.today().next(.sunday) // Oct 20, 2019 at 9:21 AM
Date.today().previous(.sunday) // Oct 13, 2019 at 9:21 AM
Date.today().previous(.monday) // Oct 14, 2019 at 9:21 AM
Date.today().previous(.thursday) // Oct 10, 2019 at 9:21 AM
Date.today().next(.thursday) // Oct 17, 2019 at 9:21 AM
Date.today().previous(.thursday,
considerToday: true) // Oct 10, 2019 at 9:21 AM
Date.today().next(.monday)
.next(.sunday)
.next(.thursday) // Oct 31, 2019 at 9:21 AM
这里是日期扩展，
extension Date {
static func today() -> Date {
return Date()
}
func next(_ weekday: Weekday, considerToday: Bool = false) -> Date {
return get(.next,
weekday,
considerToday: considerToday)
}
func previous(_ weekday: Weekday, considerToday: Bool = false) -> Date {
return get(.previous,
weekday,
considerToday: considerToday)
}
func get(_ direction: SearchDirection,
_ weekDay: Weekday,
considerToday consider: Bool = false) -> Date {
let dayName = weekDay.rawValue
let weekdaysName = getWeekDaysInEnglish().map { [=11=].lowercased() }
assert(weekdaysName.contains(dayName), "weekday symbol should be in form \(weekdaysName)")
let searchWeekdayIndex = weekdaysName.firstIndex(of: dayName)! + 1
let calendar = Calendar(identifier: .gregorian)
if consider && calendar.component(.weekday, from: self) == searchWeekdayIndex {
return self
}
var nextDateComponent = calendar.dateComponents([.hour, .minute, .second], from: self)
nextDateComponent.weekday = searchWeekdayIndex
let date = calendar.nextDate(after: self,
matching: nextDateComponent,
matchingPolicy: .nextTime,
direction: direction.calendarSearchDirection)
return date!
}
}
// MARK: Helper methods
extension Date {
func getWeekDaysInEnglish() -> [String] {
var calendar = Calendar(identifier: .gregorian)
calendar.locale = Locale(identifier: "en_US_POSIX")
return calendar.weekdaySymbols
}
enum Weekday: String {
case monday, tuesday, wednesday, thursday, friday, saturday, sunday
}
enum SearchDirection {
case next
case previous
var calendarSearchDirection: Calendar.SearchDirection {
switch self {
case .next:
return .forward
case .previous:
return .backward
}
}
}
}
您可以使用日历 ISO8601，其中第一个工作日是星期一：
Swift 5.2 或更高版本
extension Calendar {
static let iso8601 = Calendar(identifier: .iso8601)
static let iso8601UTC: Calendar = {
var calendar = Calendar(identifier: .iso8601)
calendar.timeZone = TimeZone(identifier: "UTC")!
return calendar
}()
}
let monday =
Calendar.iso8601.dateComponents([.calendar, .yearForWeekOfYear, .weekOfYear], from: Date()).date! // "Nov 9, 2020 at 12:00 AM"
print(monday.description(with: .current)) // "Monday, November 9, 2020 at 12:00:00 AM Brasilia Standard Time\n"
let mondayUTC =
Calendar.iso8601UTC.dateComponents([.calendar, .yearForWeekOfYear, .weekOfYear], from: Date()).date! // "Nov 8, 2020 at 9:00 PM" TimeZone -03:00
print(mondayUTC) // "2020-11-09 00:00:00 +0000\n"
作为 Date 计算机实施 属性 扩展名：
extension Date {
var mondayOfTheSameWeek: Date {
Calendar.iso8601.dateComponents([.calendar, .yearForWeekOfYear, .weekOfYear], from: self).date!
}
var mondayOfTheSameWeekAtUTC: Date {
Calendar.iso8601UTC.dateComponents([.calendar, .yearForWeekOfYear, .weekOfYear], from: self).date!
}
}
let mondayOfTheSameWeek = Date().mondayOfTheSameWeek // "Nov 9, 2020 at 12:00 AM"
print(mondayOfTheSameWeek.description(with: .current)) // "Monday, November 9, 2020 at 12:00:00 AM Brasilia Standard Time\n"
let mondayOfTheSameWeekAtUTC = Date().mondayOfTheSameWeekAtUTC // "Nov 8, 2020 at 9:00 PM"
print(mondayOfTheSameWeekAtUTC) // "2020-11-09 00:00:00 +0000\n"
@Saneep 回答的补充
如果您想根据 given/current 日期获得准确的日期时间（假设您想将星期一的日期时间 -> 23-05-2016 12:00:00 转换为 23-05-2016 05:35:17），那么试试这个：
func convertDate(date: NSDate, toGivendate: NSDate) -> NSDate {
let calendar = NSCalendar.currentCalendar()
let comp = calendar.components([.Year, .Month, .Day, .Hour, .Minute, .Second], fromDate: toGivendate)
let hour = comp.hour
let minute = comp.minute
let second = comp.second
let dateComp = calendar.components([.Year, .Month, .Day], fromDate: date)
let year = dateComp.year
let month = dateComp.month
let day = dateComp.day
let components = NSDateComponents()
components.year = year
components.month = month
components.day = day
components.hour = hour
components.minute = minute
components.second = second
let newConvertedDate = calendar.dateFromComponents(components)
return newConvertedDate!
}
这是我创建的扩展程序，首先找到星期日然后添加一天
extension Date {
var startOfWeek: Date? {
let gregorian = Calendar(identifier: .gregorian)
guard let sunday = gregorian.date(from: gregorian.dateComponents([.yearForWeekOfYear, .weekOfYear], from: self)) else { return nil }
return gregorian.date(byAdding: .day, value: 1, to: sunday)
}
}
这是
用法：
Date().next(.monday)
Date().next(.monday, considerToday: true)
Date().next(.monday, direction: .backward)
分机：
public func next(_ weekday: Weekday,
direction: Calendar.SearchDirection = .forward,
considerToday: Bool = false) -> Date
{
let calendar = Calendar(identifier: .gregorian)
let components = DateComponents(weekday: weekday.rawValue)
if considerToday &&
calendar.component(.weekday, from: self) == weekday.rawValue
{
return self
}
return calendar.nextDate(after: self,
matching: components,
matchingPolicy: .nextTime,
direction: direction)!
}
public enum Weekday: Int {
case sunday = 1, monday, tuesday, wednesday, thursday, friday, saturday
}
Swift 4 解
我已经根据我的要求弄清楚了，在那里我找到了关注的日期。
1. Today
2. Tomorrow
3. This Week
4. This Weekend
5. Next Week
6. Next Weekend
所以，我创建了 Date Extension 来获取 本周 和 下周 的日期。
代码
extension Date {
func getWeekDates() -> (thisWeek:[Date],nextWeek:[Date]) {
var tuple: (thisWeek:[Date],nextWeek:[Date])
var arrThisWeek: [Date] = []
for i in 0..<7 {
arrThisWeek.append(Calendar.current.date(byAdding: .day, value: i, to: startOfWeek)!)
}
var arrNextWeek: [Date] = []
for i in 1...7 {
arrNextWeek.append(Calendar.current.date(byAdding: .day, value: i, to: arrThisWeek.last!)!)
}
tuple = (thisWeek: arrThisWeek,nextWeek: arrNextWeek)
return tuple
}
var tomorrow: Date {
return Calendar.current.date(byAdding: .day, value: 1, to: noon)!
}
var noon: Date {
return Calendar.current.date(bySettingHour: 12, minute: 0, second: 0, of: self)!
}
var startOfWeek: Date {
let gregorian = Calendar(identifier: .gregorian)
let sunday = gregorian.date(from: gregorian.dateComponents([.yearForWeekOfYear, .weekOfYear], from: self))
return gregorian.date(byAdding: .day, value: 1, to: sunday!)!
}
func toDate(format: String) -> String {
let formatter = DateFormatter()
formatter.dateFormat = format
return formatter.string(from: self)
}
}
用法：
let arrWeekDates = Date().getWeekDates() // Get dates of Current and Next week.
let dateFormat = "MMM dd" // Date format
let thisMon = arrWeekDates.thisWeek.first!.toDate(format: dateFormat)
let thisSat = arrWeekDates.thisWeek[arrWeekDates.thisWeek.count - 2].toDate(format: dateFormat)
let thisSun = arrWeekDates.thisWeek[arrWeekDates.thisWeek.count - 1].toDate(format: dateFormat)
let nextMon = arrWeekDates.nextWeek.first!.toDate(format: dateFormat)
let nextSat = arrWeekDates.nextWeek[arrWeekDates.nextWeek.count - 2].toDate(format: dateFormat)
let nextSun = arrWeekDates.nextWeek[arrWeekDates.nextWeek.count - 1].toDate(format: dateFormat)
print("Today: \(Date().toDate(format: dateFormat))") // Sep 26
print("Tomorrow: \(Date().tomorrow.toDate(format: dateFormat))") // Sep 27
print("This Week: \(thisMon) - \(thisSun)") // Sep 24 - Sep 30
print("This Weekend: \(thisSat) - \(thisSun)") // Sep 29 - Sep 30
print("Next Week: \(nextMon) - \(nextSun)") // Oct 01 - Oct 07
print("Next Weekend: \(nextSat) - \(nextSun)") // Oct 06 - Oct 07
您可以根据需要修改Extension。
谢谢！
简单代码（记住要更好地照顾可选项）：
let now = Date()
var calendar = Calendar(identifier: .gregorian)
let timeZone = TimeZone(identifier: "UTC")!
let desiredWeekDay = 2
let weekDay = calendar.component(.weekday, from: now)
var weekDayDate = calendar.date(bySetting: .weekday, value: desiredWeekDay, of: now)!
/// Swift will give back the closest day matching the value above so we need to manipulate it to be always included at cuurent week.
if weekDayDate > now, weekDay > desiredWeekDay {
weekDayDate = weekDayDate - 7*24*60*60
}
print(weekDayDate)