如何检查一个是否NSDate属于今天？
我曾经使用[aDate description]. [[aDate description] substringToIndex:10]像"YYYY-MM-DD"这样返回字符串，我将字符串与返回的字符串进行了比较[[[NSDate date] description] substringToIndex:10]。
是否有更快速和/或更简洁的检查方式？
谢谢。
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72365 次
20 回答
315
在 macOS 10.9+ 和 iOS 8+ 中，NSCalendar/Calendar 上有一个方法可以做到这一点！
- (BOOL)isDateInToday:(NSDate *)date
所以你只需做
目标-C：
BOOL today = [[NSCalendar currentCalendar] isDateInToday:date];
斯威夫特 3：
let today = Calendar.current.isDateInToday(date)
于 2014-03-24T03:34:21.083 回答
192
您可以比较日期组件：
NSDateComponents *otherDay = [[NSCalendar currentCalendar] components:NSCalendarUnitEra | NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay fromDate:aDate];
NSDateComponents *today = [[NSCalendar currentCalendar] components:NSCalendarUnitEra | NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay fromDate:[NSDate date]];
if([today day] == [otherDay day] &&
[today month] == [otherDay month] &&
[today year] == [otherDay year] &&
[today era] == [otherDay era]) {
//do stuff
}
编辑：
我更喜欢 stefan 的方法，我认为它使 if 语句更清晰、更容易理解：
NSCalendar *cal = [NSCalendar currentCalendar];
NSDateComponents *components = [cal components:(NSCalendarUnitEra | NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay) fromDate:[NSDate date]];
NSDate *today = [cal dateFromComponents:components];
components = [cal components:(NSCalendarUnitEra | NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay) fromDate:aDate];
NSDate *otherDate = [cal dateFromComponents:components];
if([today isEqualToDate:otherDate]) {
//do stuff
}
克里斯，我已经采纳了你的建议。我必须查一下是什么时代，所以对于其他不知道的人来说，它区分了公元前和公元。这对大多数人来说可能是不必要的，但它很容易检查并增加了一些确定性，所以我把它包括在内。如果你追求速度，这可能不是一个好方法。
请注意，与 SO 上的许多答案一样，7 年后这完全过时了。在 Swift 现在只需使用.isDateInToday
于 2010-02-25T02:23:39.120 回答
27
这是您问题的一个分支，但如果您想打印带有“今天”或“昨天”的 NSDate，请使用该功能
- (void)setDoesRelativeDateFormatting:(BOOL)b
对于 NSDateFormatter
于 2011-01-29T05:09:44.593 回答
16
我会尝试将今天的日期标准化为午夜和第二个日期，标准化为午夜，然后比较它是否是相同的 NSDate。
从Apple 示例中，您可以将今天的日期标准化为午夜，对第二个日期执行相同操作并进行比较：
NSCalendar * gregorian = [[NSCalendar alloc]
initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents * components =
[gregorian components:
(NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit)
fromDate:[NSDate date]];
NSDate * today = [gregorian dateFromComponents:components];
于 2010-02-25T02:40:07.723 回答
14
使用Catfish_Man建议的Swift 3 和 4 扩展：
extension Date {
func isToday() -> Bool {
return Calendar.current.isDateInToday(self)
}
}
于 2016-09-06T11:46:26.183 回答
12
无需处理组件、时代和其他东西。
NSCalendar 提供了一种方法来获取现有日期的某个时间单位的开始。
此代码将获取今天的开始日期和另一个日期并进行比较。如果计算结果为NSOrderedSame，则两个日期都在同一天 - 所以今天。
NSDate *today = nil;
NSDate *beginningOfOtherDate = nil;
NSDate *now = [NSDate date];
[[NSCalendar currentCalendar] rangeOfUnit:NSDayCalendarUnit startDate:&today interval:NULL forDate:now];
[[NSCalendar currentCalendar] rangeOfUnit:NSDayCalendarUnit startDate:&beginningOfOtherDate interval:NULL forDate:beginningOfOtherDate];
if([today compare:beginningOfOtherDate] == NSOrderedSame) {
//otherDate is a date in the current day
}
于 2013-07-14T17:53:31.003 回答
9
extension NSDate {
func isToday() -> Bool {
let cal = NSCalendar.currentCalendar()
var components = cal.components([.Era, .Year, .Month, .Day], fromDate:NSDate())
let today = cal.dateFromComponents(components)!
components = cal.components([.Era, .Year, .Month, .Day], fromDate:self)
let otherDate = cal.dateFromComponents(components)!
return today.isEqualToDate(otherDate)
}
在 Swift 2.0 上为我工作
于 2015-11-03T11:50:56.670 回答
6
Swift 版本的最佳答案：
let cal = NSCalendar.currentCalendar()
var components = cal.components([.Era, .Year, .Month, .Day], fromDate:NSDate())
let today = cal.dateFromComponents(components)!
components = cal.components([.Era, .Year, .Month, .Day], fromDate:aDate);
let otherDate = cal.dateFromComponents(components)!
if(today.isEqualToDate(otherDate)) {
//do stuff
}
于 2015-04-09T13:27:12.803 回答
5
您还可以检查您拥有的日期和当前日期之间的时间间隔：
[myDate timeIntervalSinceNow]
这将为您提供 myDate 和当前日期/时间之间的时间间隔（以秒为单位）。
链接。
编辑：大家注意：我很清楚 [myDate timeIntervalSinceNow] 并没有明确地确定 myDate 是否是今天。
我将保留此答案，以便如果有人正在寻找类似的东西并且 [myDate timeIntervalSinceNow] 很有用，他们可能会在这里找到它。
于 2010-02-25T02:30:43.010 回答
5
请参阅 Apple 的文档条目，标题为“执行日历计算” [链接]。
该页面上的清单 13 建议要确定几天之间的午夜数，您可以使用：
- (NSInteger)midnightsFromDate:(NSDate *)startDate toDate:(NSDate *)endDate
{
NSCalendar *calendar = [NSCalendar autoupdatingCurrentCalendar];
NSInteger startDay = [calendar ordinalityOfUnit:NSDayCalendarUnit
inUnit:NSEraCalendarUnit
forDate:startDate];
NSInteger endDay = [calendar ordinalityOfUnit:NSDayCalendarUnit
inUnit:NSEraCalendarUnit
forDate:endDate];
return endDay - startDay;
}
然后，您可以通过使用该方法并查看它是否返回 0 来确定两天是否相同。
于 2013-07-14T17:41:39.883 回答
4
基于最佳答案的 Swift 扩展：
extension NSDate {
func isToday() -> Bool {
let cal = NSCalendar.currentCalendar()
if cal.respondsToSelector("isDateInToday:") {
return cal.isDateInToday(self)
}
var components = cal.components((.CalendarUnitEra | .CalendarUnitYear | .CalendarUnitMonth | .CalendarUnitDay), fromDate:NSDate())
let today = cal.dateFromComponents(components)!
components = cal.components((.CalendarUnitEra | .CalendarUnitYear | .CalendarUnitMonth | .CalendarUnitDay), fromDate:self);
let otherDate = cal.dateFromComponents(components)!
return today.isEqualToDate(otherDate)
}
}
于 2015-08-05T10:58:48.983 回答
2
如果你有很多这些日期比较，那么calendar:components:fromDate开始调用会占用大量时间。根据我所做的一些分析，它们似乎相当昂贵。
假设您正在尝试从某个日期数组中确定哪些日期NSArray *datesToCompare与某个给定日期相同，例如NSDate *baseDate，那么您可以使用类似以下的内容（部分改编自上面的答案）：
NSDate *baseDate = [NSDate date];
NSArray *datesToCompare = [NSArray arrayWithObjects:[NSDate date],
[NSDate dateWithTimeIntervalSinceNow:100],
[NSDate dateWithTimeIntervalSinceNow:1000],
[NSDate dateWithTimeIntervalSinceNow:-10000],
[NSDate dateWithTimeIntervalSinceNow:100000],
[NSDate dateWithTimeIntervalSinceNow:1000000],
[NSDate dateWithTimeIntervalSinceNow:50],
nil];
// determine the NSDate for midnight of the base date:
NSCalendar* calendar = [NSCalendar currentCalendar];
NSDateComponents* comps = [calendar components:(NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit)
fromDate:baseDate];
NSDate* theMidnightHour = [calendar dateFromComponents:comps];
// set up a localized date formatter so we can see the answers are right!
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateStyle:NSDateFormatterMediumStyle];
[dateFormatter setTimeStyle:NSDateFormatterMediumStyle];
// determine which dates in an array are on the same day as the base date:
for (NSDate *date in datesToCompare) {
NSTimeInterval interval = [date timeIntervalSinceDate:theMidnightHour];
if (interval >= 0 && interval < 60*60*24) {
NSLog(@"%@ is on the same day as %@", [dateFormatter stringFromDate:date], [dateFormatter stringFromDate:baseDate]);
}
else {
NSLog(@"%@ is NOT on the same day as %@", [dateFormatter stringFromDate:date], [dateFormatter stringFromDate:baseDate]);
}
}
输出：
Nov 23, 2011 1:32:00 PM is on the same day as Nov 23, 2011 1:32:00 PM
Nov 23, 2011 1:33:40 PM is on the same day as Nov 23, 2011 1:32:00 PM
Nov 23, 2011 1:48:40 PM is on the same day as Nov 23, 2011 1:32:00 PM
Nov 23, 2011 10:45:20 AM is on the same day as Nov 23, 2011 1:32:00 PM
Nov 24, 2011 5:18:40 PM is NOT on the same day as Nov 23, 2011 1:32:00 PM
Dec 5, 2011 3:18:40 AM is NOT on the same day as Nov 23, 2011 1:32:00 PM
Nov 23, 2011 1:32:50 PM is on the same day as Nov 23, 2011 1:32:00 PM
于 2011-11-23T21:37:36.497 回答
2
有比上述许多答案更简单的方法！
NSDate *date = ... // The date you wish to test
NSCalendar *calendar = [NSCalendar currentCalendar];
if([calendar isDateInToday:date]) {
//do stuff
}
于 2016-08-14T23:50:12.407 回答
0
这可能会被重新设计为 NSDate 类别，但我使用了：
// Seconds per day (24h * 60m * 60s)
#define kSecondsPerDay 86400.0f
+ (BOOL) dateIsToday:(NSDate*)dateToCheck
{
// Split today into components
NSCalendar* gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents* comps = [gregorian components:(NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit|NSHourCalendarUnit|NSMinuteCalendarUnit|NSSecondCalendarUnit)
fromDate:[NSDate date]];
// Set to this morning 00:00:00
[comps setHour:0];
[comps setMinute:0];
[comps setSecond:0];
NSDate* theMidnightHour = [gregorian dateFromComponents:comps];
[gregorian release];
// Get time difference (in seconds) between date and then
NSTimeInterval diff = [dateToCheck timeIntervalSinceDate:theMidnightHour];
return ( diff>=0.0f && diff<kSecondsPerDay );
}
（但是，在原始问题中比较两个日期字符串几乎感觉“更干净”..）
于 2010-02-26T15:07:47.523 回答
0
对于 iOS7 及更早版本：
//this is now => need that for the current date
NSDate * now = [NSDate date];
NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
[calendar setTimeZone:[NSTimeZone systemTimeZone]];
NSDateComponents * components = [calendar components:( NSYearCalendarUnit| NSMonthCalendarUnit | NSDayCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit) fromDate: now];
[components setMinute:0];
[components setHour:0];
[components setSecond:0];
//this is Today's Midnight
NSDate *todaysMidnight = [calendar dateFromComponents: components];
//now timeIntervals since Midnight => in seconds
NSTimeInterval todayTimeInterval = [now timeIntervalSinceDate: todaysMidnight];
//now timeIntervals since OtherDate => in seconds
NSTimeInterval otherDateTimeInterval = [now timeIntervalSinceDate: otherDate];
if(otherDateTimeInterval > todayTimeInterval) //otherDate is not in today
{
if((otherDateTimeInterval - todayTimeInterval) <= 86400) //86400 == a day total seconds
{
@"yesterday";
}
else
{
@"earlier";
}
}
else
{
@"today";
}
now = nil;
calendar = nil;
components = nil;
todaysMidnight = nil;
NSLog("Thank you :-)");
于 2014-09-18T10:57:13.153 回答
0
检查我们的 Erica Sadun 的伟大NSDate extension。使用非常简单。在这里罚款：
http://github.com/erica/NSDate-Extensions
它已经在这篇文章中了：https ://stackoverflow.com/a/4052798/362310
于 2015-04-09T11:50:03.230 回答
0
无需强制解包的正确且安全的解决方案，适用于 Swift 2.2 和 iOS 8 之前的版本：
func isToday() -> Bool {
let calendar = NSCalendar.currentCalendar()
if #available(iOS 8.0, *) {
return calendar.isDateInToday(self)
}
let todayComponents = calendar.components([.Era, .Year, .Month, .Day], fromDate:NSDate())
let dayComponents = calendar.components([.Era, .Year, .Month, .Day], fromDate:self)
guard let today = calendar.dateFromComponents(todayComponents),
day = calendar.dateFromComponents(dayComponents) else {
return false
}
return today.compare(day) == .OrderedSame
}
于 2016-05-05T19:45:20.503 回答
-1
这是我基于已接受答案的 2 美分答案，但也支持较新的 API。注意：我使用公历，因为大多数时间戳都是 GMT，但您可以根据需要更改您的时间戳
func isDateToday(date: NSDate) -> Bool {
let calendar = NSCalendar(calendarIdentifier: NSCalendarIdentifierGregorian)!
if calendar.respondsToSelector("isDateInToday:") {
return calendar.isDateInToday(date)
}
let dateComponents = NSCalendarUnit.CalendarUnitYear | NSCalendarUnit.CalendarUnitMonth | NSCalendarUnit.CalendarUnitDay
let today = calendar.dateFromComponents(calendar.components(dateComponents, fromDate: NSDate()))!
let dateToCompare = calendar.dateFromComponents(calendar.components(dateComponents, fromDate: date))!
return dateToCompare == today
}
于 2015-04-24T11:01:43.703 回答
-3
我的解决方案是通过除法计算自 1970 年以来经过了多少天并比较整数部分
#define kOneDay (60*60*24)
- (BOOL)isToday {
NSInteger offset = [[NSTimeZone defaultTimeZone] secondsFromGMT];
NSInteger days =[self timeIntervalSince1970] + offset;
NSInteger currentDays = [[NSDate date] timeIntervalSince1970] + offset;
return (days / kOneDay == currentDays / kOneDay);
}
于 2013-01-28T06:40:59.143 回答
-4
NSDate *dateOne = yourDate;
NSDate *dateTwo = [NSDate date];
switch ([dateOne compare:dateTwo])
{
case NSOrderedAscending:
NSLog(@”NSOrderedAscending”);
break;
case NSOrderedSame:
NSLog(@”NSOrderedSame”);
break;
case NSOrderedDescending:
NSLog(@”NSOrderedDescending”);
break;
}
于 2010-12-07T08:03:53.877 回答