比较NSDate的某些组件？

Question

我如何只比较2 NSDates的年 - 月 - 日组件？

Answer 1

因此，这里是你会怎么做：

NSCalendar *calendar = [NSCalendar currentCalendar]; 
NSInteger desiredComponents = (NSDayCalendarUnit | 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 day/month/year as secondDate 
} 

基本上，我们采取了两个日期，剁下自己的时间 - 分 - 秒位，把它们放回日期。然后，我们比较这些日期（不再有时间分量;只有日期分量），并看看他们如何比较彼此。

_{警告：在浏览器中键入并且未编译。警告实施者}

Answer 2

退房这个话题NSDate get year/month/day

一旦你拔出日/月/年，你可以把它们比为整数。

如果你不喜欢这种方法

相反，你可以试试这个..

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init]; 

[dateFormatter setDateFormat:@"yyyy"]; 
int year = [[dateFormatter stringFromDate:[NSDate date]] intValue]; 

[dateFormatter setDateFormat:@"MM"]; 
int month = [[dateFormatter stringFromDate:[NSDate date]] intValue]; 

[dateFormatter setDateFormat:@"dd"]; 
int day = [[dateFormatter stringFromDate:[NSDate date]] intValue]; 

• 而另一种方式......

  NSDateComponents *dateComp = [calendar components:unitFlags fromDate:date]; 
  
  NSInteger year = [dateComp year]; 
  
  NSInteger month = [dateComp month]; 
  
  NSInteger day = [dateComp day]; 
  

Answer 3

用-[NSDate compare:]方法 - NSDate Compare Reference

Answer 4

从iOS 8开始，您可以使用-compareDate:toDate:toUnitGranularity:方法NSCalendar。

像这样：

NSComparisonResult comparison = [[NSCalendar currentCalendar] compareDate:date1 toDate:date2 toUnitGranularity:NSCalendarUnitDay]; 

的