我如何将NSString像“01/02/10”（意思是2010年2月1日）转换为NSDate？我怎么能把NSDate变回一个字符串？
更新：2018年
字符串到日期
var dateString = "02-03-2017"
var dateFormatter = DateFormatter()
// This is important - we set our input date format to match our input string
// if the format doesn't match you'll get nil from your string, so be careful
dateFormatter.dateFormat = "dd-MM-yyyy"
//`date(from:)` returns an optional so make sure you unwrap when using.
var dateFromString: Date? = dateFormatter.date(from: dateString)
字符串的日期
var formatter = DateFormatter()
formatter.dateFormat = "dd-MM-yyyy"
guard let unwrappedDate = dateFromString else { return }
//Using the dateFromString variable from before.
let stringDate: String = formatter.string(from: dateFromString)
更新时间：2017年7月20日
字符串到NSDate
var dateString = "02-03-2017"
var dateFormatter = DateFormatter()
// This is important - we set our input date format to match our input string
// if the format doesn't match you'll get nil from your string, so be careful
dateFormatter.dateFormat = "dd-MM-yyyy"
var dateFromString = dateFormatter.date(from: dateString)
NSDate到String
var formatter = DateFormatter()
formatter.dateFormat = "dd-MM-yyyy"
let stringDate: String = formatter.string(from: dateFromString)
更新时间：2015年10月22日
字符串到NSDate
var dateString = "01-02-2010"
var dateFormatter = NSDateFormatter()
// this is imporant - we set our input date format to match our input string
dateFormatter.dateFormat = "dd-MM-yyyy"
// voila!
var dateFromString = dateFormatter.dateFromString(dateString)
NSDate到String
var formatter = NSDateFormatter()
formatter.dateFormat = "dd-MM-yyyy"
let stringDate: String = formatter.stringFromDate(NSDate())
println(stringDate)
NSString到NSDate
NSString *dateString = @"01-02-2010";
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"dd-MM-yyyy"];
NSDate *dateFromString = [dateFormatter dateFromString:dateString];
NSDate转换为NSString：
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"dd-MM-yyyy"];
NSString *stringDate = [dateFormatter stringFromDate:[NSDate date]];
NSLog(@"%@", stringDate);
如果有人有兴趣在Swift这样做这样的事情，我有一个开始的东西，虽然它并不完美。
func detectDate(dateString: NSString) -> NSDate {
var error: NSError?
let detector: NSDataDetector = NSDataDetector.dataDetectorWithTypes(NSTextCheckingType.Date.toRaw(), error: &error)!
if error == nil {
var matches = detector.matchesInString(dateString, options: nil, range: NSMakeRange(0, dateString.length))
let currentLocale = NSLocale.currentLocale()
for match in matches {
match.resultType == NSTextCheckingType.Date
NSLog("Date: \(match.date.description)")
return match.date
}
}
return NSDate()
}
NSString的日期
NSString *dateString = [NSString stringWithFormat:@"%@",[NSDate date]];
NSLog(@"string: %@",dateString ); //2015-03-24 12:28:49 +0000
NSString到NSDate
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"yyyy-MM-dd HH:mm:ss Z"];
NSDate *date = [formatter dateFromString:dateString];
NSLog(@"date: %@", date); //015-03-24 12:28:49 +0000
您可以使用扩展名。
extension NSDate {
//NSString to NSDate
convenience
init(dateString:String) {
let nsDateFormatter = NSDateFormatter()
nsDateFormatter.dateFormat = "yyyy-MM-dd hh:mm:ss"
// Add the locale if required here
let dateObj = nsDateFormatter.dateFromString(dateString)
self.init(timeInterval:0, sinceDate:dateObj!)
}
//NSDate to time string
func getTime() -> String {
let timeFormatter = NSDateFormatter()
timeFormatter.dateFormat = "hh:mm"
//Can also set the default styles for date or time using .timeStyle or .dateStyle
return timeFormatter.stringFromDate(self)
}
//NSDate to date string
func getDate() -> String {
let dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "dd, MMM"
return dateFormatter.stringFromDate(self)
}
//NSDate to String
func getString() -> String {
let dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd hh:mm:ss"
return dateFormatter.stringFromDate(self)
}
}
因此，执行实际代码将如下所示
var dateObjFromString = NSDate(dateString: cutDateTime)
var dateString = dateObjFromString.getDate()
var timeString = dateObjFromString.getTime()
var stringFromDate = dateObjFromString.getString()
还有一些默认方法，但我想它可能不适用于您从文档中提供的格式
-dateFromString(_:)
-stringFromDate(_:)
-localizedStringFromDate(_ date: NSDate,
dateStyle dateStyle: NSDateFormatterStyle,
timeStyle timeStyle: NSDateFormatterStyle) -> String
最佳实践是建立一个通用类，您可以将所有常用方法，方法用于几乎所有项目，并将@Pavan建议的代码添加为：
+ (NSDate *)getDateOutOfString:(NSString *)passedString andDateFormat:(NSString *)dateFormat{
NSString *dateString = passedString;
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:dateFormat];
NSDate *dateFromString = [[NSDate alloc] init];
dateFromString = [dateFormatter dateFromString:dateString];
return dateFromString;
}
..等等所有其他有用的方法
通过这样做，您可以开始为您的应用程序构建一个干净的可重用代码。干杯!
按照Swift 2.2
您可以从NSDate中的String和String中轻松获取NSDate。例如
首先设置日期格式化程序
let formatter = NSDateFormatter();
formatter.dateStyle = NSDateFormatterStyle.MediumStyle
formatter.timeStyle = .NoStyle
formatter.dateFormat = "MM/dd/yyyy"
现在从字符串获取日期，反之亦然。
let strDate = formatter.stringFromDate(NSDate())
print(strDate)
let dateFromStr = formatter.dateFromString(strDate)
print(dateFromStr)
现在享受。
NSString到NSDate或NSDate到NSString
//This method is used to get NSDate from string
//Pass the date formate ex-"dd-MM-yyyy hh:mm a"
+ (NSDate*)getDateFromString:(NSString *)dateString withFormate:(NSString *)formate {
// Converted date from date string
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setLocale:[[NSLocale alloc] initWithLocaleIdentifier:@"en_US"]];
[dateFormatter setDateFormat:formate];
NSDate *convertedDate = [dateFormatter dateFromString:dateString];
return convertedDate;
}
//This method is used to get the NSString for NSDate
//Pass the date formate ex-"dd-MM-yyyy hh:mm a"
+ (NSString *)getDateStringFromDate:(NSDate *)date withFormate:(NSString *)formate {
// Converted date from date string
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
//[dateFormatter setLocale:[[NSLocale alloc] initWithLocaleIdentifier:@"en_US"]];
[dateFormatter setDateFormat:formate];
NSString *convertedDate = [dateFormatter stringFromDate:date];
return convertedDate;
}
以上示例不仅仅是针对Swift 3.0+编写的
更新 - Swift 3.0+ - 将日期转换为字符串
let date = Date() // insert your date data here
var dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd" // add custom format if you'd like
var dateString = dateFormatter.string(from: date)
字符串到目前为止
var dateFormatter = DateFormatter()
dateFormatter.format = "dd/MM/yyyy"
var dateFromString: Date? = dateFormatter.date(from: dateString) //pass string here
字符串日期
var dateFormatter = DateFormatter()
dateFormatter.dateFormat = "dd-MM-yyyy"
let newDate = dateFormatter.string(from: date) //pass Date here
更新2019年（斯威夫特4）：
做了Date扩展。它使用NSDataDetector而不是NSDateFormatter。
// Just throw at it without any format.
var date: Date? = Date.FromString("02-14-2019 17:05:05")
非常愉快，它甚至可以识别“明天在5”这样的事情。
XCTAssertEqual(Date.FromString("2019-02-14"), Date.FromCalendar(2019, 2, 14))
XCTAssertEqual(Date.FromString("2019.02.14"), Date.FromCalendar(2019, 2, 14))
XCTAssertEqual(Date.FromString("2019/02/14"), Date.FromCalendar(2019, 2, 14))
XCTAssertEqual(Date.FromString("2019 Feb 14"), Date.FromCalendar(2019, 2, 14))
XCTAssertEqual(Date.FromString("2019 Feb 14th"), Date.FromCalendar(2019, 2, 14))
XCTAssertEqual(Date.FromString("20190214"), Date.FromCalendar(2019, 2, 14))
XCTAssertEqual(Date.FromString("02-14-2019"), Date.FromCalendar(2019, 2, 14))
XCTAssertEqual(Date.FromString("02.14.2019 5:00 PM"), Date.FromCalendar(2019, 2, 14, 17))
XCTAssertEqual(Date.FromString("02/14/2019 17:00"), Date.FromCalendar(2019, 2, 14, 17))
XCTAssertEqual(Date.FromString("14 February 2019 at 5 hour"), Date.FromCalendar(2019, 2, 14, 17))
XCTAssertEqual(Date.FromString("02-14-2019 17:05:05"), Date.FromCalendar(2019, 2, 14, 17, 05, 05))
XCTAssertEqual(Date.FromString("17:05, 14 February 2019 (UTC)"), Date.FromCalendar(2019, 2, 14, 17, 05))
XCTAssertEqual(Date.FromString("02-14-2019 17:05:05 GMT"), Date.FromCalendar(2019, 2, 14, 17, 05, 05))
XCTAssertEqual(Date.FromString("02-13-2019 Tomorrow"), Date.FromCalendar(2019, 2, 14))
XCTAssertEqual(Date.FromString("2019 Feb 14th Tomorrow at 5"), Date.FromCalendar(2019, 2, 14, 17))
如下：
extension Date
{
public static func FromString(_ dateString: String) -> Date?
{
// Date detector.
let detector = try! NSDataDetector(types: NSTextCheckingResult.CheckingType.date.rawValue)
// Enumerate matches.
var matchedDate: Date?
var matchedTimeZone: TimeZone?
detector.enumerateMatches(
in: dateString,
options: [],
range: NSRange(location: 0, length: dateString.utf16.count),
using:
{
(eachResult, _, _) in
// Lookup matches.
matchedDate = eachResult?.date
matchedTimeZone = eachResult?.timeZone
// Convert to GMT (!) if no timezone detected.
if matchedTimeZone == nil, let detectedDate = matchedDate
{ matchedDate = Calendar.current.date(byAdding: .second, value: TimeZone.current.secondsFromGMT(), to: detectedDate)! }
})
// Result.
return matchedDate
}
}
更新2014年：
为此做了一个NSString扩展。
// Simple as this.
date = dateString.dateValue;
感谢NSDataDetector，它识别了很多格式。
'2014-01-16' dateValue is <2014-01-16 11:00:00 +0000>
'2014.01.16' dateValue is <2014-01-16 11:00:00 +0000>
'2014/01/16' dateValue is <2014-01-16 11:00:00 +0000>
'2014 Jan 16' dateValue is <2014-01-16 11:00:00 +0000>
'2014 Jan 16th' dateValue is <2014-01-16 11:00:00 +0000>
'20140116' dateValue is <2014-01-16 11:00:00 +0000>
'01-16-2014' dateValue is <2014-01-16 11:00:00 +0000>
'01.16.2014' dateValue is <2014-01-16 11:00:00 +0000>
'01/16/2014' dateValue is <2014-01-16 11:00:00 +0000>
'16 January 2014' dateValue is <2014-01-16 11:00:00 +0000>
'01-16-2014 17:05:05' dateValue is <2014-01-16 16:05:05 +0000>
'01-16-2014 T 17:05:05 UTC' dateValue is <2014-01-16 17:05:05 +0000>
'17:05, 1 January 2014 (UTC)' dateValue is <2014-01-01 16:05:00 +0000>
eppz!kit的一部分，从GitHub抓住类别NSString+EPPZKit.h。
原始答案2013：
无论您是否（或不关心）字符串中包含的日期格式，请使用NSDataDetector来解析日期。
//Role players.
NSString *dateString = @"Wed, 03 Jul 2013 02:16:02 -0700";
__block NSDate *detectedDate;
//Detect.
NSDataDetector *detector = [NSDataDetector dataDetectorWithTypes:NSTextCheckingAllTypes error:nil];
[detector enumerateMatchesInString:dateString
options:kNilOptions
range:NSMakeRange(0, [dateString length])
usingBlock:^(NSTextCheckingResult *result, NSMatchingFlags flags, BOOL *stop)
{ detectedDate = result.date; }];
使用固定格式日期时，您需要将日期格式化程序区域设置为"en_US_POSIX"。
如果您正在使用固定格式的日期，则应首先将日期格式化程序的区域设置设置为适合您的固定格式的区域设置。在大多数情况下，最佳选择的语言环境是en_US_POSIX，这是一种专门设计用于产生美国英语结果的语言环境，无论用户和系统偏好如何。 en_US_POSIX在时间上也是不变的（如果美国，在未来的某个时刻，它会改变格式化日期的方式，en_US将改变以反映新行为，但en_US_POSIX将不会），以及平台之间（en_US_POSIX在iPhone上的工作原理相同）操作系统与OS X上的操作系统一样，并且与其他平台上的操作系统相同。
Swift 3或更高版本
extension Formatter {
static let customDate: DateFormatter = {
let formatter = DateFormatter()
formatter.locale = Locale(identifier: "en_US_POSIX")
formatter.dateFormat = "dd/MM/yy"
return formatter
}()
static let time: DateFormatter = {
let formatter = DateFormatter()
formatter.locale = Locale(identifier: "en_US_POSIX")
formatter.dateFormat = "HH:mm"
return formatter
}()
static let weekdayName: DateFormatter = {
let formatter = DateFormatter()
formatter.dateFormat = "cccc"
return formatter
}()
static let month: DateFormatter = {
let formatter = DateFormatter()
formatter.dateFormat = "LLLL"
return formatter
}()
}
extension Date {
var customDate: String {
return Formatter.customDate.string(from: self)
}
var customTime: String {
return Formatter.time.string(from: self)
}
var weekdayName: String {
return Formatter.weekdayName.string(from: self)
}
var monthName: String {
return Formatter.month.string(from: self)
}
}
extension String {
var customDate: Date? {
return Formatter.customDate.date(from: self)
}
}
用法：
// this will be displayed like this regardless of the user and system preferences
Date().customTime // "16:50"
Date().customDate // "06/05/17"
// this will be displayed according to user and system preferences
Date().weekdayName // "Saturday"
Date().monthName // "May"
解析自定义日期并将日期转换回相同的字符串格式：
let dateString = "01/02/10"
if let date = dateString.customDate {
print(date.customDate) // "01/02/10\n"
print(date.monthName) // customDate
}
在这里，您可以使用所有元素来根据需要自定义它：
为什么不向NSString添加类别？
// NSString+Date.h
@interface NSString (Date)
+ (NSDate*)stringDateFromString:(NSString*)string;
+ (NSString*)stringDateFromDate:(NSDate*)date;
@end
// NSString+Date.m
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc]init];
[dateFormatter setDateFormat:@"EEE, dd MMM yyyy HH:mm:ss ZZZ"];
NSDate *date = [dateFormatter dateFromString:stringDate ];
[dateFormatter release];
+ (NSDateFormatter*)stringDateFormatter
{
static NSDateFormatter* formatter = nil;
if (formatter == nil)
{
formatter = [[NSDateFormatter alloc] init];
[formatter setDateFormat:@"EEE, dd MMM yyyy HH:mm:ss ZZZ"];
}
return formatter;
}
+ (NSDate*)stringDateFromString:(NSString*)string
{
return [[NSString stringDateFormatter] dateFromString:string];
}
+ (NSString*)stringDateFromDate:(NSDate*)date
{
return [[NSString stringDateFormatter] stringFromDate:date];
}
// Usage (#import "NSString+Date.h") or add in "YOUR PROJECT".pch file
NSString* string = [NSString stringDateFromDate:[NSDate date]];
NSDate* date = [NSString stringDateFromString:string];
使用“10”代表一年并不好，因为它可能是1910年，1810年等。你可能应该使用4位数。
如果你可以改变日期
yyyymmdd
然后你可以使用：
// Convert string to date object
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:@"yyyyMMdd"];
NSDate *date = [dateFormat dateFromString:dateStr];
// Convert date object to desired output format
[dateFormat setDateFormat:@"EEEE MMMM d, YYYY"];
dateStr = [dateFormat stringFromDate:date];
[dateFormat release];
NSString *dateStr = @"Tue, 25 May 2010 12:53:58 +0000";
// Convert string to date object
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:@"EE, d LLLL yyyy HH:mm:ss Z"];
NSDate *date = [dateFormat dateFromString:dateStr];
[dateFormat release];
// Convert string to date
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:@"yyyyMMdd"];
NSDate *date = [dateFormat dateFromString:dateStr];
// Convert Date to string
[dateFormat setDateFormat:@"EEEE MMMM d, YYYY"];
dateStr = [dateFormat stringFromDate:date];
[dateFormat release];
NSString *mystr=@"Your string date";
NSCalendar *cal = [NSCalendar currentCalendar];
NSDate *now = [dateFormatter dateFromString:mystr];
Nslog(@"%@",now);
如果要设置格式，请使用以下代码：
NSString *dateString = @"01-02-2010";
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
// this is important - we set our input date format to match our input string
// if format doesn't match you'll get nil from your string, so be careful
[dateFormatter setDateFormat:@"dd-MM-yyyy"];
NSDate *dateFromString = [[NSDate alloc] init];
// voila!
dateFromString = [dateFormatter dateFromString:dateString];
Nslog(@"%@",[dateFormatter dateFromString:dateString]);
使用此方法从NSString转换为NSdate：
-(NSDate *)getDateFromString:(NSString *)pstrDate
{
NSDateFormatter* myFormatter = [[NSDateFormatter alloc] init];
[myFormatter setDateFormat:@"dd/MM/yyyy"];
NSDate* myDate = [myFormatter dateFromString:pstrDate];
return myDate;
}