Swift: String to ints without special function - swift

Question

I'm searching for a build-in function for converting a string like
"01092030" (format "[[dd]hh]mmss") to four individual integers.
dd => 01
hh => 09
mm => 20
ss => 30
dd and hh are optional. If missing they should be 0. I could do it by by developing a special function, but I like to use something like a regular expression.

Answer 1

I don't see the point of your "build-in function" or "regular expression" requirements, but whatever...
let s = "092030" as NSString
let pattern = "\\d\\d"
let reg = try! NSRegularExpression(pattern: pattern, options: [])
let matches = reg.matchesInString(s as String, options: [], range: NSMakeRange(0, s.length))
var result = matches.map {s.substringWithRange($0.range)}
while result.count < 4 {
result.insert("0", atIndex: 0)
}
// result is: ["0", "09", "20", "30"]
I'm also a little unclear on your output requirements. On the one hand, you say you want four "individual integers". But "09" is not an integer; it's a string representing an integer. So it seems to me that you actually want strings. If so, then result is the desired result. If not, then you need one more step:
let result2 = result.map{Int($0)!}
// result2 is: [0, 9, 20, 30]

Answer 2

Since the string contains date components you could alternatively use NSDateFormatter
let string = "01092030"
let dateFormatter = NSDateFormatter()
let dayMissing = string.characters.count < 8
let hourMissing = string.characters.count < 6
dateFormatter.dateFormat = hourMissing ? "mmss" : dayMissing ? "HHmmss" : "ddHHmmss"
let date = dateFormatter.dateFromString(string)!
let components = NSCalendar.currentCalendar().components([.Day, .Hour, .Minute, .Second], fromDate: date)
let second = components.second
let minute = components.minute
let hour = components.hour
let day = dayMissing ? 0 : components.day