Convert long month name to int

Question

I understand how to use an NSDateFormatter to convert a month component into a long name string, but how does one convert a month name to an int?

I've been using a switch statement to convert, but I'm thinking there must be a simpler way.

For example, I'd like to convert "May" to 5.

Answer 1

You can use DateFormatter custom format "LLLL" to parse your date string (Month). If you are only parsing dates in english you should set the date formatter locale to "en_US_POSIX":

let df = DateFormatter()
df.locale = Locale(identifier: "en_US_POSIX")
df.dateFormat = "LLLL"  // if you need 3 letter month just use "LLL"
if let date = df.date(from: "May") {
    let month = Calendar.current.component(.month, from: date)
    print(month)  // 5
}

Answer 2

Thanks Josh. I've converted the Obj-C code and posted it below for future reference:

let calendar = NSCalendar(identifier: NSCalendarIdentifierGregorian)
let components = NSDateComponents()
let formatter = NSDateFormatter()
formatter.dateFormat = "MMMM"
let aDate = formatter.dateFromString("May")
let components1 = calendar!.components(.CalendarUnitMonth , fromDate: aDate!)
let monthInt = components.month

Answer 3

Use MM for the month format. Use stringFromDate to convert your NSDate to a String. Then convert your string to an Int with .toInt()

let dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "MM"
let monthString = dateFormatter.stringFromDate(NSDate()) // "05"
let monthInt = monthString.toInt() // 5

Answer 4

NSDateFormatter has monthSymbols property. Try:

let formatter = NSDateFormatter()
formatter.calendar = NSCalendar(identifier: NSCalendarIdentifierGregorian)

let monthString = "September"
let month = find(formatter.monthSymbols as! [String], monthString).map { $0 + 1 }
// -> Optional(9)

let monthString2 = "Foobar"
let month2 = find(formatter.monthSymbols as! [String], monthString2).map { $0 + 1 }
// -> nil