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
为什么不给NSString添加一个category ?
// 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];
其他回答
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; }];
// 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];
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!
根据Swift 2.2
你可以很容易地得到NSDate从字符串和字符串从NSDate。 如。
第一次设置日期格式化程序
let formatter = NSDateFormatter();
formatter.dateStyle = NSDateFormatterStyle.MediumStyle
formatter.timeStyle = .NoStyle
formatter.dateFormat = "MM/dd/yyyy"
现在从字符串中获取date,反之亦然。
let strDate = formatter.stringFromDate(NSDate())
print(strDate)
let dateFromStr = formatter.dateFromString(strDate)
print(dateFromStr)
现在享受。
NSString *mystr=@"Your string date";
NSCalendar *cal = [NSCalendar currentCalendar];
NSDate *now = [dateFormatter dateFromString:mystr];
Nslog(@"%@",now);
如果你想设置格式使用下面的代码:
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]);
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