swift Date

Posted 2023-02-24 ihoudf

作者：想聽丿伱說衹愛我
链接：https://www.jianshu.com/p/3170a2e7d16a
来源：简书
著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。

一、简介

可使用DateFormatter将Date格式化成字符串，经常通过Calendar和DateComponents来获取符合某条件的Date。

二、API

1. 获取1970到2001年的间隔（秒）

public static let timeIntervalBetween1970AndReferenceDate: TimeInterval

print(Date.timeIntervalBetween1970AndReferenceDate)
//978307200.0

1. 获取2001-1-1 00:00:00到现在的间隔（秒）

public static var timeIntervalSinceReferenceDate: TimeInterval  get 

print(Date.timeIntervalSinceReferenceDate)
//629172967.099814

1. 初始化方法

• 当前日期

public init()

print(Date())
//2020-12-09 02:18:16 +0000

• 当前日期偏移多少秒后的日期

public init(timeIntervalSinceNow: TimeInterval)

print(Date(), Date(timeIntervalSinceNow: 10), separator: "\\n")
//2020-12-09 02:22:05 +0000
//2020-12-09 02:22:15 +0000

• 1970-01-01 00:00:00偏移多少秒后的日期

public init(timeIntervalSince1970: TimeInterval)

print(Date(timeIntervalSince1970: 10))
//1970-01-01 00:00:10 +0000

• 日期date偏移多少秒后的日期

public init(timeInterval: TimeInterval, since date: Date)

print(Date(timeInterval: 10, since: Date()), Date(timeIntervalSinceNow: 10), 
                                                            separator: "\\n")
//2020-12-09 02:27:21 +0000
//2020-12-09 02:27:21 +0000

• 2001-01-01 00:00:00偏移多少秒后的日期

public init(timeIntervalSinceReferenceDate ti: TimeInterval)

print(Date(timeIntervalSinceReferenceDate: 10))
//2001-01-01 00:00:10 +0000

1. 时间间隔

• 与2001-01-01 00:00:00的间隔（秒）

public var timeIntervalSinceReferenceDate: TimeInterval  get 

let d = Date()
print(d.timeIntervalSinceReferenceDate)
//629173835.230096

• 与时间date的间隔（秒）

public func timeIntervalSince(_ date: Date) -> TimeInterval

let d = Date()
print(d.timeIntervalSince(Date(timeIntervalSinceNow: 10)))
//-10.000119924545288

• 与当前时间的间隔（秒）

public var timeIntervalSinceNow: TimeInterval  get 

let d = Date(timeIntervalSinceNow: 10)
print(d.timeIntervalSinceNow)
//9.999890923500061

• 与1970-01-01 00:00:00的间隔（秒）

public var timeIntervalSince1970: TimeInterval  get 

let d = Date()
print(d.timeIntervalSince1970)
//1607481591.40725

1. 返回偏移多少秒后的新日期

public func addingTimeInterval(_ timeInterval: TimeInterval) -> Date

相当于+ -

let d = Date()
print(d, d.addingTimeInterval(10), d+10, separator: "\\n")
//2020-12-09 02:47:55 +0000
//2020-12-09 02:48:05 +0000
//2020-12-09 02:48:05 +0000

1. 日期偏移多少秒

public mutating func addTimeInterval(_ timeInterval: TimeInterval)

突变方法 相当于+= -=

        var d = Date()
        print(d)
        d.addTimeInterval(10)
        print(d)
        d+=10
        print(d)
//2020-12-09 02:48:35 +0000
//2020-12-09 02:48:45 +0000
//2020-12-09 02:48:55 +0000

1. 获取一个遥远的将来的日期

public static let distantFuture: Date

print(Date.distantFuture)
//4001-01-01 00:00:00 +0000

1. 获取一个遥远的过去的日期

public static let distantPast: Date

print(Date.distantPast)
//0001-01-01 00:00:00 +0000

8.比较另一个日期

public func compare(_ other: Date) -> ComparisonResult

enum ComparisonResult : Int 
    case orderedAscending = -1//升序 <
    case orderedSame = 0      //相等 =
    case orderedDescending = 1//降序 >

var d = Date()
print(d.compare(d+10).rawValue)
//-1

1. 比较符与运算符

//两日期是否相等
public static func == (lhs: Date, rhs: Date) -> Bool
//左日期是否小于右日期
public static func < (lhs: Date, rhs: Date) -> Bool
//左日期是否大于右日期
public static func > (lhs: Date, rhs: Date) -> Bool
//相当于addingTimeInterval方法
public static func + (lhs: Date, rhs: TimeInterval) -> Date
public static func - (lhs: Date, rhs: TimeInterval) -> Date
//相当于addTimeInterval方法
public static func += (lhs: inout Date, rhs: TimeInterval)
public static func -= (lhs: inout Date, rhs: TimeInterval)

1. 日期描述

• 通用描述

public var description: String  get 

默认按YYYY-MM-DD HH:MM:SS ±HHMM输出日期，±HHMM代表时区与UTC的时差，以小时和分钟为单位

var d = Date()
print(d, d.description, separator: "\\n")
//2020-12-09 03:16:05 +0000
//2020-12-09 03:16:05 +0000

• 本地化描述

public func description(with locale: Locale?) -> String

传nil时与description相同

let d = Date()
print(d.description, d.description(with: nil), 
      d.description(with: Locale(identifier: "zh")),  separator: "\\n")
//2020-12-09 03:18:09 +0000
//2020-12-09 03:18:09 +0000
//2020年12月9日 星期三 中国标准时间 上午11:18:09

1. Strideable协议

• 与日期other的距离（秒）

public func distance(to other: Date) -> TimeInterval

与timeIntervalSince方法的结果值为正负

let d = Date()
print(d.distance(to: d+10))
print(d.timeIntervalSince(d+10))
//10.0
//-10.0

• 返回增加多少秒后的新日期

public func advanced(by n: TimeInterval) -> Date

与addingTimeInterval相同

let d = Date()
print(d, d.advanced(by: 10), d.addingTimeInterval(10), separator: "\\n")
//2020-12-09 03:31:19 +0000
//2020-12-09 03:31:29 +0000
//2020-12-09 03:31:29 +0000