ios 将 NSString 转换为 NSDate（并再次返回）
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/3917250/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Converting NSString to NSDate (and back again)
提问by cannyboy
How would I convert an NSStringlike "01/02/10" (meaning 1st February 2010) into an NSDate? And how could I turn the NSDateback into a string?
我如何将NSString类似“ 01/02/10”（意味着 2010 年 2 月 1 日）转换为NSDate？我怎么能把NSDate背变成一根绳子？
回答by Pavan
Swift 4 and later
Swift 4 及更高版本
Updated: 2018
更新时间：2018
String to Date
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)
Date to String
日期到字符串
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)
Swift 3
斯威夫特 3
Updated: 20th July 2017
更新时间：2017 年 7 月 20 日
String to NSDate
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 to String
NSDate 到字符串
var formatter = DateFormatter()
formatter.dateFormat = "dd-MM-yyyy"
let stringDate: String = formatter.string(from: dateFromString)
Swift
迅速
Updated: 22nd October 2015
更新时间：2015 年 10 月 22 日
String to NSDate
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 to String
NSDate 到字符串
var formatter = NSDateFormatter()
formatter.dateFormat = "dd-MM-yyyy"
let stringDate: String = formatter.stringFromDate(NSDate())
println(stringDate)
Objective-C
目标-C
NSString to NSDate
NSString 到 NSDate
NSString *dateString = @"01-02-2010";
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"dd-MM-yyyy"];
NSDate *dateFromString = [dateFormatter dateFromString:dateString];
NSDate convert to NSString:
NSDate 转换为 NSString：
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"dd-MM-yyyy"];
NSString *stringDate = [dateFormatter stringFromDate:[NSDate date]];
NSLog(@"%@", stringDate);
回答by Geri Borbás
UPDATE 2019 (Swift 4):
2019 年更新（Swift 4）：
Made a Dateextensionfor that. It uses NSDataDetectorinstead of NSDateFormatter.
为此做了一个Date扩展。它使用NSDataDetector代替NSDateFormatter.
// Just throw at it without any format.
var date: Date? = Date.FromString("02-14-2019 17:05:05")
Pretty enjoyable, it even recognizes things like "Tomorrow at 5".
非常有趣，它甚至可以识别诸如“明天 5 点”之类的内容。
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))
Goes like:
像：
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
}
}
UPDATE 2014:
2014 年更新：
Made an NSString extensionfor that.
为此做了一个NSString 扩展。
// Simple as this.
date = dateString.dateValue;
Thanks to NSDataDetector, it recognizes a whole lot of format.
感谢NSDataDetector，它可以识别很多格式。
'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>
Part of eppz!kit, grab the category NSString+EPPZKit.hfrom GitHub.
部分eppz！套件，抢类别的NSString + EPPZKit.h从GitHub。
ORIGINAL ANSWER 2013:
2013 年的原始答案：
Whether you're not sure (or don't care) about the date format contained in the string, use NSDataDetector for parsing date.
无论您不确定（或不关心）字符串中包含的日期格式，请使用 NSDataDetector 来解析 date。
//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; }];
回答by Leo Dabus
When using fixed-format dates you need to set the date formatter locale to "en_US_POSIX".
使用固定格式日期时，您需要将日期格式化程序语言环境设置为"en_US_POSIX".
Taken from the Data Formatting Guide
取自数据格式指南
If you're working with fixed-format dates, you should first set the locale of the date formatter to something appropriate for your fixed format. In most cases the best locale to choose is en_US_POSIX, a locale that's specifically designed to yield US English results regardless of both user and system preferences. en_US_POSIX is also invariant in time (if the US, at some point in the future, changes the way it formats dates, en_US will change to reflect the new behavior, but en_US_POSIX will not), and between platforms (en_US_POSIX works the same on iPhone OS as it does on OS X, and as it does on other platforms).
如果您使用固定格式的日期，您应该首先将日期格式化程序的区域设置为适合您的固定格式的内容。在大多数情况下，要选择的最佳语言环境是 en_US_POSIX，这是一种专门设计用于产生美国英语结果 而不管用户和系统首选项的语言环境。en_US_POSIX 在时间上也是不变的（如果美国在未来的某个时候改变了它格式化日期的方式，en_US 将改变以反映新的行为，但 en_US_POSIX 不会），并且在平台之间（en_US_POSIX 在 iPhone 上的工作方式相同OS 在 OS X 上的操作，以及在其他平台上的操作）。
Swift 3 or later
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)
}
}
usage:
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"
Parsing the custom date and converting the date back to the same string format:
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
}
Here it is all elements you can use to customize it as necessary:
这是您可以根据需要自定义它的所有元素：
回答by Sveinung Kval Bakken
Why not add a category to NSString?
为什么不给 NSString 添加一个类别？
// 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];
回答by DuckDucking
using "10" for representing a year is not good, because it can be 1910, 1810, etc. You probably should use 4 digits for that.
使用“10”代表一年是不好的，因为它可以是1910，1810，等你或许应该使用4个位数为。
If you can change the date to something like
如果您可以将日期更改为类似
yyyymmdd
Then you can use:
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];
回答by Mohit
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];
回答by Rushabh
// 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];
回答by Akhtar
Use this method to convert from NSStringto NSdate:
使用此方法转换NSString为NSdate：
-(NSDate *)getDateFromString:(NSString *)pstrDate
{
NSDateFormatter* myFormatter = [[NSDateFormatter alloc] init];
[myFormatter setDateFormat:@"dd/MM/yyyy"];
NSDate* myDate = [myFormatter dateFromString:pstrDate];
return myDate;
}
回答by Kyle
If anyone is interested in doing something like this in Swift these days, I have a start on something, although it's not perfect.
如果现在有人对在 Swift 中做这样的事情感兴趣，我有一个开始，尽管它并不完美。
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()
}
回答by mahesh chowdary
NSString *mystr=@"Your string date";
NSCalendar *cal = [NSCalendar currentCalendar];
NSDate *now = [dateFormatter dateFromString:mystr];
Nslog(@"%@",now);
If you want set the format use below code:
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]);
