如何在Swift中以短格式获取当前日期

Question

在下面的图片中,您可以看到我编写的代码和所有变量的值:

class fun getCurrentShortDate() -> String {
    var todaysDate = NSDate()
    var dateFormatter = NSDateFormatter()
    dateFormatter.dateFormat = "dd-MM-yyyy"
    var DateInFormat = dateFormatter.stringFromDate(todaysDate)

    return DateInFormat
}

变量值

正如您所看到的那样,当前日期没有问题,但是当我尝试将NSDate更改为字符串时,它就不会这样做了.

Answer 1

Xcode 8或更高版本•Swift 3或更高版本

extension TimeZone {
    static let gmt = TimeZone(secondsFromGMT: 0)!
}
extension Formatter {
    static let date = DateFormatter()
}

extension Date {
    func localizedDescription(dateStyle: DateFormatter.Style = .medium,
                              timeStyle: DateFormatter.Style = .medium,
                           in timeZone : TimeZone = .current,
                              locale   : Locale = .current) -> String {
        Formatter.date.locale = locale
        Formatter.date.timeZone = timeZone
        Formatter.date.dateStyle = dateStyle
        Formatter.date.timeStyle = timeStyle
        return Formatter.date.string(from: self)
    }
    var localizedDescription: String { return localizedDescription() }
}

Date().localizedDescription                                                // "Sep 26, 2018 at 12:03:41 PM"
Date().localizedDescription(in: .gmt)                                      // "Sep 26, 2018 at 3:03:41 PM" UTC TIME
Date().localizedDescription(dateStyle: .short, timeStyle: .short)          //  "9/26/18, 12:03 PM"
Date().localizedDescription(dateStyle: .full, timeStyle: .full)            //  "Wednesday, September 26, 2018 at 12:03:41 PM Brasilia Standard Time"
Date().localizedDescription(dateStyle: .full, timeStyle: .full, in: .gmt)  // "Wednesday, September 26, 2018 at 3:03:41 PM Greenwich Mean Time"

extension Date {
    var fullDate:  String { return localizedDescription(dateStyle: .full, timeStyle: .none)  }
    var shortDate: String { return localizedDescription(dateStyle: .short, timeStyle: .none)  }
    var fullTime:  String { return localizedDescription(dateStyle: .none, timeStyle: .full)  }
    var shortTime: String { return localizedDescription(dateStyle: .none, timeStyle: .short)   }
    var fullDateTime:  String { return localizedDescription(dateStyle: .full, timeStyle: .full)  }
    var shortDateTime: String { return localizedDescription(dateStyle: .short, timeStyle: .short)  }
}

print(Date().fullDate)  // "Friday, May 26, 2017\n"
print(Date().shortDate)  // "5/26/17\n"

print(Date().fullTime)  // "10:16:24 AM Brasilia Standard Time\n"
print(Date().shortTime)  // "10:16 AM\n"

print(Date().fullDateTime)  // "Friday, May 26, 2017 at 10:16:24 AM Brasilia Standard Time\n"
print(Date().shortDateTime)  // "5/26/17, 10:16 AM\n"

Answer 2

SWIFT 4 或 5

extension Date {

 static func getCurrentDate() -> String {

        let dateFormatter = DateFormatter()

        dateFormatter.dateFormat = "dd/MM/yyyy HH:mm:ss"

        return dateFormatter.string(from: Date())

    }
}

使用

print(Date.getCurrentDate())

Answer 3

Swift 3.0更新:为. 创建扩展Date

extension Date {
    func string(format: String) -> String {
        let formatter = DateFormatter()
        formatter.dateFormat = format
        return formatter.string(from: self)
    }
}

用法:

Date().string(format: "yyyy-MM-dd")

Swift 2.2:为. 创建扩展NSDate

extension NSDate {  
    func dateStringWithFormat(format: String) -> String {
        let dateFormatter = NSDateFormatter()
        dateFormatter.dateFormat = format
        return dateFormatter.stringFromDate(self)
    }   
}

用法:

NSDate().dateStringWithFormat("yyyy-MM-dd")

Answer 4

您可以创建一个扩展名,以便轻松地将a String转换为a NSDate.

extension NSDate {
    func dateFromString(date: String, format: String) -> NSDate {
        let formatter = NSDateFormatter()
        let locale = NSLocale(localeIdentifier: "en_US_POSIX")

        formatter.locale = locale
        formatter.dateFormat = format

        return formatter.dateFromString(date)!
    }
}

比你的功能,你可以NSDate().dateFromString("2015-02-04 23:29:28", format: "yyyy-MM-dd HH:mm:ss"),这应该工作.输入日期不需要与输出日期的格式相同.

func getCurrentShortDate() -> String {
    var todaysDate = NSDate().dateFromString("2015-02-04 23:29:28", format:  "yyyy-MM-dd HH:mm:ss")

    var dateFormatter = NSDateFormatter()
    dateFormatter.dateFormat = "dd-MM-yyyy"
    var DateInFormat = dateFormatter.stringFromDate(todaysDate)

    return DateInFormat
}

println(getCurrentShortDate())

输出是04-02-2015.

Answer 5

斯威夫特 3

使用由 @doovers 创建的扩展和来自本网站的一些格式字符串，您将获得以下内容：

extension Date {
    func string(format: String) -> String {
        let formatter = DateFormatter()
        formatter.dateFormat = format
        return formatter.string(from: self)
    }
}

用法：

Date().string(format: "EEEE, MMM d, yyyy") // Saturday, Oct 21, 2017
Date().string(format: "MM/dd/yyyy")        // 10/21/2017
Date().string(format: "MM-dd-yyyy HH:mm")  // 10-21-2017 03:31

Date().string(format: "MMM d, h:mm a")     // Oct 21, 3:31 AM
Date().string(format: "MMMM yyyy")         // October 2017
Date().string(format: "MMM d, yyyy")       // Oct 21, 2017

Date().string(format: "E, d MMM yyyy HH:mm:ss Z") // Sat, 21 Oct 2017 03:31:40 +0000
Date().string(format: "yyyy-MM-dd'T'HH:mm:ssZ")   // 2017-10-21T03:31:40+0000
Date().string(format: "dd.MM.yy")                 // 21.10.17

您还可以将毫秒传递给日期对象，如下所示：

Date(1508577868947).string(format: "EEEE, MMM d, yyyy") // Saturday, Oct 21, 2017