Parsing a Swift String to Date, then Components - swift

Question

I have a date "2017-12-31" as a String.
What I want to get finally is only the month: "12" as a String.
So I thought that I can change it to Date using a date formatter
let formatter = DateFormatter()
formatter.dateFormat = "MM"
What do I do next?

Answer 1

let dateString = "2017-12-31"
let formatter = DateFormatter()
formatter.calendar = Calendar(identifier: Calendar.Identifier.iso8601) formatter.timeZone = TimeZone(identifier: TimeZone.autoupdatingCurrent.identifier)
formatter.dateFormat = "yyyy-MM-dd"
let localDate = formatter.date(from: dateString)
formatter.dateFormat = "MM"
let strMonth = formatter.string(from: localDate!)
print("Month is:",strMonth)
Another way
let dateString = "2017-12-31"
let formatter = DateFormatter()
formatter.dateFormat = "yyyy-MM-dd"
let localDate = formatter.date(from: dateString)
let month = String(NSCalendar.current.component(.month, from: localDate!))
print(month)

Answer 2

First you have to use the DateFormatter to create a temporary Date object from your source String object. Then you have to use it to create your final String from the temporary Date object.
let dateString = "2017-12-31"
let dateFormatter = DateFormatter()
// set the dateFormatter's dateFormat to the dateString's format
dateFormatter.dateFormat = "yyyy-MM-dd"
// create date object
guard let tempDate = dateFormatter.date(from: dateString) else {
fatalError("wrong dateFormat")
}
// set the dateFormatter's dateFormat to the output format you wish to receive
dateFormatter.dateFormat = "LL" // LL is the stand-alone month
let month = dateFormatter.string(from: tempDate)

Answer 3

Use below function for getting month from string file of date
func getMonthFromDateString(strDate: String) -> String {
let formatter = DateFormatter()
formatter.dateFormat = "yyyy-MM-dd"
let date = formatter.date(from: strDate) // Convert String File To Date
formatter.dateFormat = "MM"
let strMM = formatter.string(from: date!) // Convert date to string
return strMM
}