SwiftDate使用笔记

SwiftDate新版本有一些重大更新，删除了原DateFormat，并且增加了一些新的东西。

1、String转Date

SwiftDate能够自动识别主流的时间格式（ISO8601, RSS, Alt RSS, .NET, SQL, HTTP...），你也可以手动指定格式。创建一个新的Date从未如此简单过。

// All default datetime formats (15+) are recognized automatically
let _ = "2010-05-20 15:30:00".toDate()
// You can also provide your own format!
let _ = "2010-05-20 15:30".toDate("yyyy-MM-dd HH:mm")
// All ISO8601 variants are supported too with timezone parsing!
let _ = "2017-09-17T11:59:29+02:00".toISODate()
// RSS, Extended, HTTP, SQL, .NET and all the major variants are supported!
let _ = "19 Nov 2015 22:20:40 +0100".toRSS(alt: true)

2、Date操作

可以通过使用自然语言添加或删除时间组件来操纵日期。时间扩展工具简单方便，而且支持常用的时区、日历、本地操作。
可以使用标准数学运算符对日期、时间间隔、日期组件和相关时间单位之间进行操作！

// Math operations support time units
let _ = ("2010-05-20 15:30:00".toDate() + 3.months - 2.days)
let _ = Date() + 3.hours
let _ = date1 + [.year:1, .month:2, .hour:5]
let _ = date1 + date2
// extract single time unit components from date manipulation
let over1Year = (date3 - date2).year > 1

3、Date比较

SwiftDate包含一组全面的比较函数；你可以按粒度比较两个日期，检查日期是否是某一天，某一范围以及您实际需要的任何其他比较。
依然可以通过标准数学运算符（>，> =，<，<=）进行比较。

// Standard math comparison is allowed
let _ = dateA >= dateB || dateC < dateB

// Complex comparisons includes granularity support
let _ = dateA.compare(toDate: dateB, granularity: .hour) == .orderedSame
let _ = dateA.isAfterDate(dateB, orEqual: true, granularity: .month) // > until month granularity
let _ = dateC.isInRange(date: dateA, and: dateB, orEqual: true, granularity: .day) // > until day granularity
let _ = dateA.earlierDate(dateB) // earlier date
let _ = dateA.laterDate(dateB) // later date

// Check if date is close to another with a given precision
let _ = dateA.compareCloseTo(dateB, precision: 1.hours.timeInterval

// Compare for relevant events:
// .isToday, .isYesterday, .isTomorrow, .isWeekend, isNextWeek
// .isSameDay, .isMorning, .isWeekday ...
let _ = date.compare(.isToday)
let _ = date.compare(.isNight)
let _ = date.compare(.isNextWeek)
let _ = date.compare(.isThisMonth)
let _ = date.compare(.startOfWeek)
let _ = date.compare(.isNextYear)
// ...and MORE THAN 30 OTHER COMPARISONS BUILT IN

// Operation in arrays (oldestIn, newestIn, sortedByNewest, sortedByOldest...)
let _ = DateInRegion.oldestIn(list: datesArray)
let _ = DateInRegion.sortedByNewest(list: datesArray)

4、使用Region（Timezone, Calendar & Locale）创建Date

您可以从字符串，时间间隔或使用日期组件创建新日期。 SwiftDate提供了一系列功能来创建和推倒您的日期，甚至随机生成！

// All dates includes timezone, calendar and locales!
// Create from string
let rome = Region(calendar: Calendars.gregorian, zone: Zones.europeRome, locale: Locales.italian)
let date1 = DateInRegion("2010-01-01 00:00:00", region: rome)!

// Create date from intervals
let _ = DateInRegion(seconds: 39940, region: rome)
let _ = DateInRegion(milliseconds: 5000, region: rome)

// Date from components
let _ = DateInRegion(components: {
    $0.year = 2001
    $0.month = 9
    $0.day = 11
    $0.hour = 12
    $0.minute = 0
}, region: rome)
let _ = DateInRegion(year: 2001, month: 1, day: 5, hour: 23, minute: 30, second: 0, region: rome)

// Random date generation with/without bounds
let _ = DateInRegion.randomDate(region: rome)
let _ = DateInRegion.randomDate(withinDaysBeforeToday: 5)
let _ = DateInRegion.randomDates(count: 50, between: lowerLimitDate, and: upperLimitDate, region: rome)

5、派生日期

也可以从其他日期开始生成日期，SwiftDate包含一组广泛的构造函数。 使用dateAt()函数可以轻松创建20多个不同的派生日期。

let _ = DateInRegion().dateAt(.endOfDay) // today at the end of the day
// Over 20 different relevant dates including .startOfDay,
// .endOfDay, .startOfWeek, .tomorrow, .nextWeekday, .nextMonth, .prevYear, .nearestMinute and many others!
let _ = dateA.nextWeekday(.friday) // the next friday after dateA
let _ = (date.dateAt(.startOfMonth) - 3.days)
let _ = dateA.compare(.endOfWeek)

// Enumerate dates in range by providing your own custom
// increment expressed in date components
let from = DateInRegion("2015-01-01 10:00:00", region: rome)!
let to = DateInRegion("2015-01-02 03:00:00", region: rome)!
let increment2 = DateComponents.create {
    $0.hour = 1
    $0.minute = 30
    $0.second = 10
}
// generate dates in range by incrementing +1h,30m,10s each new date
let dates = DateInRegion.enumerateDates(from: fromDate2, to: toDate2, increment: increment2)

// Altering time components
let _ = dateA.dateBySet(hour: 10, min: 0, secs: 0)

// Truncating a date
let _ = dateA.dateTruncated(at: [.year,.month,.day]) // reset all time components keeping only date

// Rounding a date
let _ = dateA.dateRoundedAt(.toMins(10))
let _ = dateA.dateRoundedAt(.toFloor30Mins)

// Adding components
let _ = dateA.dateByAdding(5,.year)

// Date at the start/end of any time component
let _ = dateA.dateAtEndOf(.year) // 31 of Dec at 23:59:59
let _ = dateA.dateAtStartOf(.day) // at 00:00:00 of the same day
let _ = dateA.dateAtStartOf(.month) // at 00:00:00 of the first day of the month

6、组成提取

您可以直接从日期中提取组件，它包括在日期区域中表示的确切值（正确时区和区域设置！）。

// Create a date in a region, London but with the lcoale set to IT
let london = Region(calendar: .gregorian, zone: .europeLondon, locale: .italian)
let date = DateInRegion("2018-02-05 23:14:45", format: dateFormat, region: london)!

// You can extract any of the all available time units.
// VALUES ARE EXPRESSED IN THE REGION OF THE DATE (THE RIGHT TIMEZONE).
// (you can still get the UTC/absolute value by getting the inner's absoluteDate).

let _ = date.year // 2018
let _ = date.month // 2
let _ = date.monthNameDefault // 'Febbraio' as the locale is the to IT!
let _ = date.firstDayOfWeek // 5
let _ = date.weekdayNameShort // 'Lun' as locale is the to IT
// ... all components are supported: .year, .month, .day, .hour, .minute, .second,
// .monthName, .weekday, .nearestHour, .firstDayOfWeek. .quarter and so on...

7、在时区/区域设置和日历之间切换

您可以轻松地将任何日期转换为其他区域（或者其他日历、区域、时区设置）！ 新日期包含表示为目标原因的所有值。

// Conversion between timezones is easy using convertTo(region:) function
let rNY = Region(calendar: Calendars.gregorian, zone: Zones.americaNewYork, locale: Locales.english)
let rRome = Region(calendar: Calendars.gregorian, zone: Zones.europeRome, locale: Locales.italian)
let dateInNY = "2017-01-01 00:00:00".toDate(region: rNY)
let dateInRome = dateInNY?.convertTo(region: rRome)!
print(dateInRome.toString()) // "dom gen 01 06:00:00 +0100 2017\n"

// You can also convert single region's attributes
let dateInIndia = dateInNY?.convertTo(timezone: Zones.indianChristmas, locale: Locales.nepaliIndia)
print("\(dateInIndia!.toString())") // "आइत जनवरी ०१ १२:००:०० +0700 २०१७\n"

8、Date格式（Date转String）

日期格式很简单，您可以指定自己的格式，区域设置或使用任何提供的格式。

// Date Formatting
let london = Region(calendar: .gregorian, zone: .europeLondon, locale: .english)
let date = ... // 2017-07-22T18:27:02+02:00 in london region
let _ = date.toDotNET() // /Date(1500740822000+0200)/
let _ = date.toISODate() // 2017-07-22T18:27:02+02:00
let _ = date.toFormat("dd MMM yyyy 'at' HH:mm") // "22 July 2017 at 18:27"

// You can also easily change locale when formatting a region
let _ = date.toFormat("dd MMM", locale: .italian) // "22 Luglio"

// Time Interval Formatting as Countdown
let interval: TimeInterval = (2.hours.timeInterval) + (34.minutes.timeInterval) + (5.seconds.timeInterval)
let _ = interval.toClock() // "2:34:05"

// Time Interval Formatting by Components
let _ = interval.toString {
    $0.maximumUnitCount = 4
    $0.allowedUnits = [.day, .hour, .minute]
    $0.collapsesLargestUnit = true
    $0.unitsStyle = .abbreviated
} // "2h 34m"

9、相对日期格式（完全可自定义！）

相对格式化是SwiftDate中的全新内容；它支持120多种语言，有两种不同的风格（.default，.twitter），9种特例（.long，.longTime，.longConvenient，.short，.shortTime，.shortConvenient，.narrow，.tiny，.quantify）而且它们全都可以根据您的需要进行定制。 可扩展格式允许您提供自己的转换和规则以覆盖默认行为。

// Twitter Style
let _ = (Date() - 3.minutes).toRelative(style: RelativeFormatter.twitterStyle(), locale: Locales.english) // "3m"
let _ = (Date() - 6.minutes).toRelative(style: RelativeFormatter.twitterStyle(), locale: Locales.italian) // "6 min fa"

// Default Style
let _ = (now2 - 5.hours).toRelative(style: RelativeFormatter.defaultStyle(), locale: Locales.english) // "5 hours ago"
let y = (now2 - 40.minutes).toRelative(style: RelativeFormatter.defaultStyle(), locale: Locales.italian) // "45 minuti fa"

10、 Codable支持

DateInRegion和Region都完全支持新的Swift的Codable协议。 这意味着您可以安全地编码/解码它们：

// Encoding/Decoding a Region
let region = Region(calendar: Calendars.gregorian, zone: Zones.europeOslo, locale: Locales.english)
let encodedJSON = try JSONEncoder().encode(region)
let decodedRegion = try JSONDecoder().decode(Region.self, from: encodedJSON)

// Encoding/Decoding a DateInRegion
let date = DateInRegion("2015-09-24T13:20:55", region: region)
let encodedDate = try JSONEncoder().encode(date)
let decodedDate = try JSONDecoder().decode(DateInRegion.self, from: encodedDate)

11、时间段

SwiftDate集成了高手Matthew York的DateTools模块，以支持时间段。
请参阅文档的“时间段”部分。