如何将字符串日期转换为NSDate？

Question

我想将“2014-07-15 06：55：14.198000 + 00:00”这个字符串日期转换为Swift中的NSDate。

Answer 1

试试这个：

let dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = /* find out and place date format from 
                            * http://userguide.icu-project.org/formatparse/datetime
                            */
let date = dateFormatter.dateFromString(/* your_date_string */)

要进一步查询，请分别检查Objective-C和Swift的基础框架的NSDateFormatter和DateFormatter类。

Swift 3及更高版本（包括Swift 4）

let dateFormatter = DateFormatter()
dateFormatter.dateFormat = /* date_format_you_want_in_string from
                            * http://userguide.icu-project.org/formatparse/datetime
                            */
guard let date = dateFormatter.date(from: /* your_date_string */) else {
   fatalError("ERROR: Date conversion failed due to mismatched format.")
}

// use date constant here

Answer 2

斯威夫特3,4：

2次有用的转换：

string(from: Date) // to convert from Date to a String
date(from: String) // to convert from String to Date

用法：1。

let date = Date() //gives today's date
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "dd.MM.yyyy"
let todaysDateInUKFormat = dateFormatter.string(from: date)

2.

 let someDateInString = "23.06.2017"
 var getDateFromString = dateFormatter.date(from: someDateInString)

Answer 3

对于SWIFT 3.1

func convertDateStringToDate(longDate: String) -> String{

    /* INPUT: longDate = "2017-01-27T05:00:00.000Z"
     * OUTPUT: "1/26/17"
     * date_format_you_want_in_string from
     * http://userguide.icu-project.org/formatparse/datetime
     */

    let dateFormatter = DateFormatter()
    dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSZ"
    let date = dateFormatter.date(from: longDate)

    if date != nil {

        let formatter = DateFormatter()
        formatter.dateStyle = .short
        let dateShort = formatter.string(from: date!)

        return dateShort

    } else {

        return longDate

    }
}

注意：如果出现错误，这将返回原始字符串

Answer 4

要在Swift中的Date Format中添加String，我就这样做了

 var dataFormatter:NSDateFormatter = NSDateFormatter()
                dataFormatter.dateFormat = "dd-MMMM 'at' HH:mm a"

cell.timeStamplbl.text = dataFormatter.stringFromDate(object.createdAt)

Answer 5

这项工作对我来说..

    import Foundation
    import UIKit

    //dateString = "01/07/2017"
    private func parseDate(_ dateStr: String) -> String {
            let simpleDateFormat = DateFormatter()
            simpleDateFormat.dateFormat = "dd/MM/yyyy" //format our date String
            let dateFormat = DateFormatter()
            dateFormat.dateFormat = "dd 'de' MMMM 'de' yyyy" //format return

            let date = simpleDateFormat.date(from: dateStr)
            return dateFormat.string(from: date!)
    }

Answer 6

Swift: iOS
if we have string, convert it to NSDate,

var dataString = profileValue["dob"] as String
var dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "MM-dd-yyyy"

// convert string into date
let dateValue:NSDate? = dateFormatter.dateFromString(dataString)

if you have and date picker parse date like this

// to avoid any nil value
if let isDate = dateValue {
self.datePicker.date = isDate
}

Answer 7

下面是一些字符串到日期格式转换选项可以在swift iOS中使用。

1. Thursday, Dec 27, 2018格式= EEEE, MMM d, yyyy
2. 12/27/2018格式= MM/dd/yyyy
3. 12-27-2018 09:59格式= MM-dd-yyyy HH:mm
4. Dec 27, 9:59 AM格式= MMM d, h:mm a
5. December 2018格式= MMMM yyyy
6. Dec 27, 2018格式= MMM d, yyyy
7. Thu, 27 Dec 2018 09:59:19 +0000格式= E, d MMM yyyy HH:mm:ss Z
8. 2018-12-27T09:59:19+0000格式= yyyy-MM-dd'T'HH:mm:ssZ
9. 27.12.18格式= dd.MM.yy
10. 09:59:19.815格式= HH:mm:ss.SSS

Answer 8

你可以尝试这个快速的代码

    let dateFormatter = DateFormatter()
    dateFormatter.dateFormat = "dd/MM/yyyy"//same as strDate date formator
    dateFormatter.timeZone = TimeZone(abbreviation: "GMT+0:00")//Must used if you get one day less in conversion
    let convertedDateObject = dateFormatter.date(from: strDate)

Answer 9

import Foundation

let now : String = "2014-07-16 03:03:34 PDT"
var date : NSDate
var dateFormatter : NSDateFormatter

date = dateFormatter.dateFromString(now)

date // $R6: __NSDate = 2014-07-16 03:03:34 PDT

https://developer.apple.com/library/prerelease/mac/documentation/Cocoa/Reference/Foundation/Classes/NSDateFormatter_Class/index.html#//apple_ref/doc/uid/20000447-SW32

Answer 10

斯威夫特4

import Foundation

let dateString = "2014-07-15" // change to your date format

var dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd"

let date = dateFormatter.date(from: dateString)
println(date)

斯威夫特3

import Foundation

var dateString = "2014-07-15" // change to your date format

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

var date = dateFormatter.dateFromString(dateString)
println(date)

我可以用这段代码来做。

Answer 11

 func convertDateFormatter(date: String) -> String
 {

    let dateFormatter = NSDateFormatter()
    dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSZ"//this your string date format
    dateFormatter.timeZone = NSTimeZone(name: "UTC")
    let date = dateFormatter.dateFromString(date)


    dateFormatter.dateFormat = "yyyy MMM EEEE HH:mm"///this is what you want to convert format
    dateFormatter.timeZone = NSTimeZone(name: "UTC")
    let timeStamp = dateFormatter.stringFromDate(date!)


    return timeStamp
}

针对Swift 3进行了更新。

func convertDateFormatter(date: String) -> String
{

    let dateFormatter = DateFormatter()
    dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSZ"//this your string date format
    dateFormatter.timeZone = NSTimeZone(name: "UTC") as TimeZone!
    let date = dateFormatter.date(from: date)


    dateFormatter.dateFormat = "yyyy MMM EEEE HH:mm"///this is what you want to convert format
    dateFormatter.timeZone = NSTimeZone(name: "UTC") as TimeZone!
    let timeStamp = dateFormatter.string(from: date!)


    return timeStamp
}

Answer 12

如果您需要经常将字符串解析为日期，则可能需要将该功能移动到扩展名中。我创建了一个sharedCode.swift文件并将扩展名放在那里：

extension String
{   
    func toDateTime() -> NSDate
    {
        //Create Date Formatter
        let dateFormatter = NSDateFormatter()

        //Specify Format of String to Parse
        dateFormatter.dateFormat = "yyyy-MM-dd hh:mm:ss.SSSSxxx"

        //Parse into NSDate
        let dateFromString : NSDate = dateFormatter.dateFromString(self)!

        //Return Parsed Date
        return dateFromString
    }
}

然后，如果您想将字符串转换为NSDate，您可以编写如下内容：

var myDate = myDateString.toDateTime()

Answer 13

细节

• Swift 4，Xcode 9.2
• Swift 5，Xcode 10.2（10E125）

解

import Foundation

extension DateFormatter {

    convenience init (format: String) {
        self.init()
        dateFormat = format
        locale = Locale.current
    }
}

extension String {

    func toDate (dateFormatter: DateFormatter) -> Date? {
        return dateFormatter.date(from: self)
    }

    func toDateString (dateFormatter: DateFormatter, outputFormat: String) -> String? {
        guard let date = toDate(dateFormatter: dateFormatter) else { return nil }
        return DateFormatter(format: outputFormat).string(from: date)
    }
}

extension Date {

    func toString (dateFormatter: DateFormatter) -> String? {
        return dateFormatter.string(from: self)
    }
}

用法

var dateString = "14.01.2017T14:54:00"
let dateFormatter = DateFormatter(format: "dd.MM.yyyy'T'HH:mm:ss")
let date = Date()

print("original String with date:               \(dateString)")
print("date String() to Date():                 \(dateString.toDate(dateFormatter: dateFormatter)!)")
print("date String() to formated date String(): \(dateString.toDateString(dateFormatter: dateFormatter, outputFormat: "dd MMMM")!)")
let dateFormatter2 = DateFormatter(format: "dd MMM HH:mm")
print("format Date():                           \(date.toString(dateFormatter: dateFormatter2)!)")

结果

更多信息

About date format

Answer 14

对于Swift 3

func stringToDate(_ str: String)->Date{
    let formatter = DateFormatter()
    formatter.dateFormat="yyyy-MM-dd hh:mm:ss Z"
    return formatter.date(from: str)!
}
func dateToString(_ str: Date)->String{
    var dateFormatter = DateFormatter()
    dateFormatter.timeStyle=DateFormatter.Style.short
    return dateFormatter.string(from: str)
}

Answer 15

The code fragments on this QA page are "upside down"...

Apple提到的第一件事是你缓存你的格式化程序......

Link to Apple doco stating exactly how to do this:

用于效率的缓存格式化器创建日期格式化程序并不是一种廉价的操作。 ...缓存单个实例...

使用全球......

let df : DateFormatter = {
    let formatter = DateFormatter()
    formatter.dateFormat = "yyyy-MM-dd"
    return formatter 
}()

然后在任何地方使用该格式化器......

let s = df.string(from: someDate)

要么

let d = df.date(from: someString)

或者在DateFormatter上使用任何其他许多方便的方法。

It is that simple.

（如果你在String上写一个扩展名，你的代码完全是“颠倒” - 你不能使用任何dateFormatter调用！）

请注意，通常你会有一些全局变量..例如“formatForClient”“formatForPubNub”“formatForDisplayOnInvoiceScreen”..等等。

Answer 16

Swift支持扩展，通过扩展，您可以为现有的class，structure，enumeration或protocol类型添加新功能。

您可以通过使用init关键字扩展对象，将新的NSDate函数添加到extension对象。

extension NSDate
{
    convenience
    init(dateString:String) {
        let dateStringFormatter = NSDateFormatter()
        dateStringFormatter.dateFormat = "yyyyMMdd"
        dateStringFormatter.locale = NSLocale(localeIdentifier: "fr_CH_POSIX")
        let d = dateStringFormatter.dateFromString(dateString)!
        self.init(timeInterval:0, sinceDate:d)
    }
} 

现在，您可以使用以下命令初始化NSDate对象：

let myDateObject = NSDate(dateString:"2010-12-15 06:00:00")

Answer 17

自Swift 3以来，许多NS前缀都已被删除。

let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss.SSSZ" 
/* date format string rules
 * http://userguide.icu-project.org/formatparse/datetime
 */

let date = dateFormatter.date(from: dateString)