How to get calendar days between two dates in swift3

Question

I'm trying to days between two dates in swift3 by following coding. Unfortunately, I got error and running failed. Please let me know how to solve and how to get calendar days between two dates in swift3.

static func getDaysList(_ startDate:String, endDate:String, interval:Int) -> [Date] {
    var dayRange = [Date]()
    let inter = TimeInterval(interval * 60 * 60)
    let ti:TimeInterval = inter
    let dateFormatter = DateFormatter()
    dateFormatter.dateFormat = datetimeformat
    let dateTo = dateFormatter.date(from: endDate)

    var nextDate = dateFormatter.date(from: startDate)
    let endDate = dateTo!.addingTimeInterval(ti)
    var startTime = NSDate()

    while nextDate!.compare(endDate) == ComparisonResult.orderedAscending {
        startTime = nextDate! as NSDate
        dayRange.append(startTime as Date)
        nextDate = nextDate!.addingTimeInterval(ti)
        startTime = nextDate! as NSDate
    }

    return dayRange
}

fatal error: unexpectedly found nil while unwrapping an Optional value

pointed to let endDate = dateTo!.addingTimeInterval(ti)

What does "get calendar days" even _mean?_ What would "good" output be? — matt, Nov 04 '16 at 15:09
I don't know what that means. I know what a date is. But what is a "day" in your mind? I'm serious: show sample input and desired output. I can't imagine what you have in mind here. — matt, Nov 04 '16 at 15:12
@matt I want to get like `['2016-11-04', '2016-11-05', '2016-11-06', '2016-11-07']` etc — PPShein, Nov 04 '16 at 15:18
@matt I know, I've created `var dates = [Date]()` and want to add those dates into that array. — PPShein, Nov 04 '16 at 15:22
It seems to me that the question is well covered by Martin's answer at the duplicate. If not, show why not. — matt, Nov 04 '16 at 15:49

Frankie · Answer 1 · 2016-11-04T15:25:30.247

-1

Here

 let dateTo = dateFormatter.date(from: endDate)

Your endDate is likely a string that is not in the correct format for your dateFormatter. Therefore dateTo ends up as nil and crashes on:

let endDate = dateTo!.addingTimeInterval(ti)

edited Nov 04 '16 at 15:25

answered Nov 04 '16 at 15:14

Frankie

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How to get calendar days between two dates in swift3

1 Answers1