get NSDate today, yesterday, this Week, last Week, this Month, last Month... variables
Adapted from the Date and Time Programming Guide:
// Right now, you can remove the seconds into the day if you want
NSDate *today = [NSDate date];
// All intervals taken from Google
NSDate *yesterday = [today dateByAddingTimeInterval: -86400.0];
NSDate *thisWeek = [today dateByAddingTimeInterval: -604800.0];
NSDate *lastWeek = [today dateByAddingTimeInterval: -1209600.0];
// To get the correct number of seconds in each month use NSCalendar
NSDate *thisMonth = [today dateByAddingTimeInterval: -2629743.83];
NSDate *lastMonth = [today dateByAddingTimeInterval: -5259487.66];
If you want the correct exact number of days depending on the month, you should use an NSCalendar
.
Might be a better way to write this but here what i came up on Ben's NSCalendar suggestion and working from there to NSDateComponents
NSCalendar *cal = [NSCalendar currentCalendar];
NSDateComponents *components = [cal components:( NSCalendarUnitHour | NSCalendarUnitMinute | NSCalendarUnitSecond ) fromDate:[[NSDate alloc] init]];
[components setHour:-[components hour]];
[components setMinute:-[components minute]];
[components setSecond:-[components second]];
NSDate *today = [cal dateByAddingComponents:components toDate:[[NSDate alloc] init] options:0]; //This variable should now be pointing at a date object that is the start of today (midnight);
[components setHour:-24];
[components setMinute:0];
[components setSecond:0];
NSDate *yesterday = [cal dateByAddingComponents:components toDate: today options:0];
components = [cal components:NSWeekdayCalendarUnit | NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit fromDate:[[NSDate alloc] init]];
[components setDay:([components day] - ([components weekday] - 1))];
NSDate *thisWeek = [cal dateFromComponents:components];
[components setDay:([components day] - 7)];
NSDate *lastWeek = [cal dateFromComponents:components];
[components setDay:([components day] - ([components day] -1))];
NSDate *thisMonth = [cal dateFromComponents:components];
[components setMonth:([components month] - 1)];
NSDate *lastMonth = [cal dateFromComponents:components];
NSLog(@"today=%@",today);
NSLog(@"yesterday=%@",yesterday);
NSLog(@"thisWeek=%@",thisWeek);
NSLog(@"lastWeek=%@",lastWeek);
NSLog(@"thisMonth=%@",thisMonth);
NSLog(@"lastMonth=%@",lastMonth);
NSDateComponents is nice to get today:
NSCalendar *cal = [NSCalendar currentCalendar];
NSDate *date = [NSDate date];
NSDateComponents *comps = [cal components:(NSYearCalendarUnit | NSMonthCalendarUnit | NSDayCalendarUnit)
fromDate:date];
NSDate *today = [cal dateFromComponents:comps];
This creates a NSDate with only year, month and date:
(gdb) po today
2010-06-22 00:00:00 +0200
To get yesterday, etc. you can calculate it using NSDateComponents:
NSDateComponents *components = [[NSDateComponents alloc] init];
[components setDay:-1];
NSDate *yesterday = [cal dateByAddingComponents:components toDate:today options:0];