将NSString转换为NSDate（并再次返回）Swift 4解决scheme可用
我如何将“ 01/02/10 ”（意思是2010年2月1日）的NSString / String转换为NSDate / Date ？ 我又怎么能把date再次变成一个string呢？
Swift 4和更高版本
更新date：2017年11月16日
string到date
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到string
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
更新date：2017年7月20日
string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)
迅速
更新date：2015年10月22日
string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)
Objective-C的
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);
为此做了一个NSString扩展 。
// Simple as this. date = dateString.dateValue;
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>
作为eppz！套件的一部分 ，从GitHub获取NSString + EPPZKit.h类别。
原始答案：无论您不确定（或不关心）string中包含的date格式，请使用NSDataDetector来parsingdate 。
//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; }];
Xcode 8.3.2•Swift 3.1
extension Formatter { static let customDate: DateFormatter = { let formatter = DateFormatter() formatter.dateFormat = "dd/MM/yy" return formatter }() static let time:DateFormatter = { let formatter = DateFormatter() 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：
Date().customTime // "16:50" Date().customDate // "06/05/17" Date().weekdayName // "Saturday" Date().monthName // "May" let dateString = "01/02/10" if let date = dateString.customDate { print(Formatter.customDate.string(from: date)) // "01-02-10\n" }
在这里，您可以根据需要使用所有元素进行自定义：
为什么不添加一个类别到NSString？
// 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];
用“10”代表一年不好，因为它可能是1910年，1810年等。你可能应该用4位数。
如果你可以改变date到类似的东西
yyyymmdd
那么你可以使用：
// 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]);
使用此方法将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; }
如果有人有兴趣在Swift这样的事情上做这样的事情，我有一个开始的东西，虽然这不是完美的。
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() }
你可以使用扩展名。
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) } }
所以虽然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()
还有一些默认的方法，但我想它可能不适用于你从文档给出的格式
-dateFromString(_:) -stringFromDate(_:) -localizedStringFromDate(_ date: NSDate, dateStyle dateStyle: NSDateFormatterStyle, timeStyle timeStyle: NSDateFormatterStyle) -> String
date到NSString
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
最好的做法是build立自己的一般类，在那里你把所有的一般使用方法，在几乎所有的项目中有用的方法，并添加由@Pavanbuild议的代码为：
+ (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; }
..等所有其他有用的方法
通过这样做，你开始为你的应用程序构build一个干净的可重用的代码。 干杯!
根据Swift 2.2
您可以轻松地从NSDate的string和string中获取NSDate。 例如
首先设置date格式化程序
let formatter = NSDateFormatter(); formatter.dateStyle = NSDateFormatterStyle.MediumStyle formatter.timeStyle = .NoStyle formatter.dateFormat = "MM/dd/yyyy"
现在从string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; }
上面的例子不是简单的为Swift 3.0+编写的
更新 – Swift 3.0+ – 将date转换为string
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)
