Swift: Substring based on a character - swift

Question

I'm getting information from an API and one of the fields is a DateTime in this format:
2014-12-12T14:44:18.973
I would like to remove the "T" and anything after it so in the end, I get:
2014-12-12
Any ideas or leads on how to do this with Swift? Unfortunately, I can't just create an NSDate out of directly as it throws an Exception.
In the end, I want to have something like 12-12-2014 in a string format.
Thanks!

Answer 1

Fortunately, You CAN just create an NSDate out of it directly as follow:
extension String {
func toDateFormattedWith(format:String)-> NSDate {
let formatter = NSDateFormatter()
// formatter.timeZone = NSTimeZone(forSecondsFromGMT: 0) // you can set GMT time
formatter.timeZone = NSTimeZone.localTimeZone() // or as local time
formatter.dateFormat = format
return formatter.dateFromString(self)!
}
}
There is many ways to pick just the date from that string. I would use the following approach:
let myDate = "2014-12-12T14:44:18.973".componentsSeparatedByString("T")[0].toDateFormattedWith("yyyy-MM-dd") // "Dec 12, 2014, 12:00 AM"
You can also create an extension to extract that info from the Date object:
public extension NSDate {
var day: Int { return NSCalendar.currentCalendar().components(NSCalendarUnit.CalendarUnitDay, fromDate: self).day }
var month: Int { return NSCalendar.currentCalendar().components(NSCalendarUnit.CalendarUnitMonth, fromDate: self).month }
var year: Int { return NSCalendar.currentCalendar().components(NSCalendarUnit.CalendarUnitYear, fromDate: self).year }
var dateAt12am: NSDate {
return NSCalendar.currentCalendar().dateWithEra(1, year: year, month: month, day: day, hour: 0, minute: 0, second: 0, nanosecond: 0)!
}
}
let myDate1 = "2014-12-12T14:44:18.973".toDateFormattedWith("yyyy-MM-dd\'T\'HH:mm:ss.SSS").dateAt12am
println(myDate1) // "2014-12-12 02:00:00 +0000" (12am local time)
If you need reference you can use this:

Answer 2

This actually isn't too bad. What you're looking for is rangeOfString() to find out where "T" is. If you call .startIndex on that, you can find out where the first occurrence of that "T" is.
Once you have that, you can just create a substring from the beginning of the string to that point like this:
let date: String = dateTime.substringWithRange(Range<String.Index>(start: dateTime.startIndex, end: dateTime.rangeOfString("T")!.startIndex))
If you wanted to take that and turn it into an NSDate, you could use an NSDateFormatter:
let formatter: NSDateFormatter = NSDateFormatter()
formatter.dateFormat = "yyyy-MM-dd"
let newDate: NSDate = formatter.dateFromString(date)! // "Dec 12, 2014, 12:00 AM"
If you don't want that time piece at the end and just want to output the date in a different style than that returned by the API, you could add this:
formatter.dateStyle = .ShortStyle // Change this to modify the style of the date that is returned in the next line
let formattedDate: String = formatter.stringFromDate(newDate) // "12/12/14"