Comparing certain components of NSDate?

Question

How would I compare only the year-month-day components of 2 NSDates?

Answer 1

So here's how you'd do it:

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
}

Basically, we take the two dates, chop off their hours-minutes-seconds bits, and the turn them back into dates. We then compare those dates (which no longer have a time component; only a date component) and see how they compare to eachother.

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