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
字符串到日期
var dateFormatter = DateFormatter()
dateFormatter.format = "dd/MM/yyyy"
var dateFromString: Date? = dateFormatter.date(from: dateString) //pass string here
日期到字符串
var dateFormatter = DateFormatter()
dateFormatter.dateFormat = "dd-MM-yyyy"
let newDate = dateFormatter.string(from: date) //pass Date here
其他回答
当使用固定格式的日期时,需要将日期格式化程序的区域设置为“en_US_POSIX”。
摘自数据格式化指南
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).
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
}
这里是你可以用来定制它的所有元素:
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];
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。
Swift 4及后续版本
更新:2018
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)
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)
斯威夫特3
更新:2017年7月20日
NSDate的字符串
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到字符串
var formatter = DateFormatter()
formatter.dateFormat = "dd-MM-yyyy"
let stringDate: String = formatter.string(from: dateFromString)
斯威夫特
更新:2015年10月22日
NSDate的字符串
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到字符串
var formatter = NSDateFormatter()
formatter.dateFormat = "dd-MM-yyyy"
let stringDate: String = formatter.stringFromDate(NSDate())
println(stringDate)
objective - c
和陌生人约会
NSString *dateString = @"01-02-2010";
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"dd-MM-yyyy"];
NSDate *dateFromString = [dateFormatter dateFromString:dateString];
首次约会:
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"dd-MM-yyyy"];
NSString *stringDate = [dateFormatter stringFromDate:[NSDate date]];
NSLog(@"%@", stringDate);
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)
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