Question

我想比较2个特定日期，但是，我想比较月份和年份，而不是天。例如，我有一个类似2016-08-16的日期，以及2016-08-10之类的其他日期，我需要比较日期并获得平等，因为他们的月份相等。

因此，我需要一种方法来使两个NSDates平等，所以我需要让2016-08-10成为2016-08-00。之后我也可以修改第二个日期并进行比较。

我有简单的代码片段用于平等，但我认为它也考虑了几天和几小时等等：

 if ([dateOld compare:dateNew] == NSOrderedDescending) {
        NSLog(@"date1 is later than date2");
    } else if ([dateOld compare:dateNew] == NSOrderedAscending) {
        NSLog(@"date1 is earlier than date2");
    } else {
        NSLog(@"dates are the same");
    }

为了使它工作，我需要“零”NSDates的日期和时间。有没有办法做到这一点？

Answer 1

请参阅此答案：Comparing certain components of NSDate?

NSCalendar *calendar = [NSCalendar currentCalendar];
NSInteger desiredComponents = (NSMonthCalendarUnit | NSYearCalendarUnit);

NSDate *firstDate = ...; // one date
NSDate *secondDate = ...; // the other date

NSDateComponents *firstComponents = [calendar components:desiredComponents fromDate:firstDate];
NSDateComponents *secondComponents = [calendar components:desiredComponents fromDate:secondDate];

NSDate *truncatedFirst = [calendar dateFromComponents:firstComponents];
NSDate *truncatedSecond = [calendar dateFromComponents:secondComponents];

NSComparisonResult result = [truncatedFirst compare:truncatedSecond];
if (result == NSOrderedAscending) {
  //firstDate is before secondDate
} else if (result == NSOrderedDescending) {
  //firstDate is after secondDate
}  else {
  //firstDate is the same month/year as secondDate
}

Answer 2

如果您有两个日期，

NSDate *now = // some date
NSDate *other = // some other date

您可以将此比较视为：

if ([[NSCalendar currentCalendar] compareDate:now toDate:other toUnitGranularity:NSCalendarUnitMonth] == NSOrderedSame) {
    NSLog(@"Same month");
} else {
    NSLog(@"Different month");
}

将NSDates天数设置为相同的值

2 个答案: