Get all NSDates BETWEEN startDate and endDate

My question is the REVERSE of the typical "How do I find out if an NSDate is between startDate and endDate?"

What I want to do is find ALL NSDATES (to the day, not hour or minute)开发者_StackOverflow that occur BETWEEN startDate and endDate. Inclusive of those dates would be preferable, although not necessary.

Example: (I know that these don't represent NSDates, these are just for illustration)

INPUT: startDate = 6/23/10 20:11:30 endDate = 6/27/10 02:15:00

OUTPUT: NSArray of: 6/23/10, 6/24/10, 6/25/10, 6/26/10, 6/27/10

I don't mind doing the work. It's just that I don't know where to start in terms of making efficient code, without having to step through the NSDates little by little.

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Use an NSCalendar instance to convert your start NSDate instance into an NSDateComponents instance, add 1 day to the NSDateComponents and use the NSCalendar to convert that back to an NSDate instance. Repeat the last two steps until you reach your end date.

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Add 24 hours to the start date until you go past the end date.

for ( nextDate = startDate ; [nextDate compare:endDate] < 0 ; nextDate = [nextDate addTimeInterval:24*60*60] ) {
  // use date
}

You could round the first date to noon or midnight before starting the loop if you care about the time of day.

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Ever since OS X 10.9 and iOS 8.0 there is the following very clean way to do this. It also deals with end of month jumps.

let cal = NSCalendar.currentCalendar()
let start = NSDate()
let end = // some end date

var next = start
while !cal.isDate(next, inSameDayAsDate: end) {
    next = cal.dateByAddingUnit(.Day, value: 1, toDate: next, options: [])!
    // do something with `next`
}

Note that for older OS versions -isDate:inSameDayAsDate: can be replaced by some call to e.g. -components:fromDate:toDate:options: and -dateByAddingUnit:value:toDate:options: can be replaced by dateByAddingComponents:toDate:options:.