我如何将一个NSString像“01/02/10”(意思是2010年2月1日)转换成一个NSDate?如何将NSDate转换回字符串?
当前回答
更新2019 (Swift 4):
为此做了一个日期扩展。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")
非常有趣，它甚至能识别像“明天5点”这样的东西。
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))
就像:
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
}
}
2014年更新:
为此做了一个NSString扩展。
// Simple as this.
date = dateString.dateValue;
多亏了NSDataDetector，它能识别很多格式。
'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>
eppz的一部分!从GitHub获取类别NSString+EPPZKit.h。
2013年的原始答案:
无论您是否确定(或不关心)字符串中包含的日期格式，都可以使用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; }];
其他回答
使用这个方法将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;
}
最好的做法是建立一个通用类，你把你所有的通用方法，在几乎所有项目中都有用的方法，并在那里添加@Pavan建议的代码:
+ (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;
}
. .所有其他有用的方法都是如此
通过这样做，你开始为你的应用程序构建一个干净的可重用代码。 干杯!
首次约会还是第一次约会
//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;
}
上面的例子不是简单地为Swift 3.0+编写的
更新- Swift 3.0+ -转换日期到字符串
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)
您可以为此使用扩展。
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，在执行时，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()
也有一些默认方法，但我猜它可能不适用于您从文档中给出的格式
-dateFromString(_:)
-stringFromDate(_:)
-localizedStringFromDate(_ date: NSDate,
dateStyle dateStyle: NSDateFormatterStyle,
timeStyle timeStyle: NSDateFormatterStyle) -> String
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