Create an Array of NSDates like in Ruby - objective-c

Question

I want to create an array of NSDates starting from today to next month. This can easily be done in Ruby using Time.now..(Time.now + 30.days)
How can I create an array of dates just like in Ruby in Objective C?

Answer 1

Any ObjC solution is unfortunately going to be far more verbose than that Ruby code.
The correct way to make the calculation is with NSDateComponents:
NSMutableArray * dateArray = [NSMutableArray array];
NSCalendar * cal = [NSCalendar currentCalendar];
NSDateComponents * plusDays = [NSDateComponents new];
NSDate * now = [NSDate date];
for( NSUInteger day = 0; day < NUMDAYS; day++ ){
[plusDays setDay:day];
[dateArray addObject:[cal dateByAddingComponents:plusDays toDate:now options:0]];
}
To make the procedure more convenient (if you need to do it more than a few times), you could put this loop into a category method on NSCalendar, with NUMDAYS replaced with the argument and substituting self for cal.

Answer 2

There's nothing built in to do this quite as concisely as the Ruby you've posted. Breaking the problem down, you need a way to get the day after a particular date. Here's a function that will do that:
NSDate *CalendarDayAfterDate(NSDate *date)
{
NSDateComponents *components = [[NSDateComponents alloc] init];
components.day = 1;
NSCalendar *calendar = [NSCalendar currentCalendar];
return [calendar dateByAddingComponents:components toDate:date options:0];
}
Next, you need to get an array of days one after the other:
NSDate *today = [NSDate date];
NSMutableArray *dates = [NSMutableArray arrayWithObject:today];
for (NSUInteger i=0; i<30; i++) {
NSDate *tomorrow = CalendarDayAfterDate(today);
[dates addObject:tomorrow];
today = tomorrow;
}

Answer 3

After much downvoting and commenting, here's my REVISED answer...
-(NSDate *)nextDayFromDate:(NSDate *)originalDate {
NSCalendar *calendar = [NSCalendar currentCalendar];
NSDateComponents *dateComponent = [NSDateComponents new];
dateComponent.day = 1;
NSDate *tomorrow = [calendar dateByAddingComponents:dateComponent toDate:originalDate options:0];
return tomorrow;
}
NSMutableArray *dateArray = [NSMutableArray array];
NSDate *now = [NSDate date];
[dateArray addObject:now];
for (int i=0;i<31;i++) {
NSDate *firstDate = [dateArray objectAtIndex:i];
NSDate *newDate = [self nextDayFromDate:firstDate];
[dateArray addObject:newDate];
}
What this does is use the NSCalendar API to add a "day interval" to any given NSDate. Add "Now" to the array, then do a loop 30 times, each time using the previous NSDate object as input to the logic.