比較NSDate的某些組件？

Question

我如何只比較2 NSDates的年 - 月 - 日組件？

Answer 1

因此，這裏是你會怎麼做：

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，我們採取了兩個日期，剁下自己的時間 - 分 - 秒位，把它們放回日期。然後，我們比較這些日期（不再有時間分量;只有日期分量），並看看他們如何比較彼此。

_{警告：在瀏覽器中鍵入並且未編譯。警告實施者}

Answer 2

退房這個話題NSDate get year/month/day

一旦你拔出日/月/年，你可以把它們比爲整數。

如果你不喜歡這種方法

相反，你可以試試這個..

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]; 

• 而另一種方式......

  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

從iOS 8開始，您可以使用-compareDate:toDate:toUnitGranularity:方法NSCalendar。

像這樣：

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

的