Make a new NSDate by combining two NSDates

Question

I have NSDate* day1 and NSDate* day2. How can I make a NSDate* day3 by copying only year/month/day from day1 and hour/minute/second from d

Answer 1

It's not as compact as darvids0n's, but it works.

NSDate* day1 = [datePicker dateValue];
NSDate* day2 = [NSDate date];

NSDateComponents *components = [[NSCalendar currentCalendar] components:NSDayCalendarUnit | NSMonthCalendarUnit | NSYearCalendarUnit fromDate:day1;
NSInteger day = [components day];    
NSInteger month = [components month];
NSInteger year = [components year];

components = [[NSCalendar currentCalendar] components:NSDayCalendarUnit | NSMonthCalendarUnit | NSYearCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit |NSSecondCalendarUnit fromDate:day2];
NSInteger hour = [components hour];    
NSInteger minute = [components minute];
NSInteger second = [components second];

NSDateComponents *comps = [[[NSDateComponents alloc] init] autorelease];
[comps setDay:day];
[comps setMonth:month];
[comps setYear:year];
[comps setHour:hour];
[comps setMinute:minute];
[comps setSecond:second];
NSCalendar *cal = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDate *day3 = [cal dateFromComponents:comps];

or

NSDateFormatter *tempFormatter = [[[NSDateFormatter alloc]init]autorelease];
[tempFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
NSString* message = [NSString stringWithFormat:@"%04d-%02d-%02d %02d:%02d:%02d", year, month, day, hour, minute, second];
NSDate *day3 = [tempFormatter dateFromString:message];