swift4 날짜 date 형식 formatting

2018-12-13

let today = Date()

        let dateFormatter = DateFormatter()

        dateFormatter.dateFormat = "yyyy-MM-dd EE"

        dateFormatter.locale = Locale(identifier: "ko_KR")

        print(dateFormatter.string(from: today))

2018. 12. 13(목)

dateFormatter.dateFormat = "yyyy. MM. dd(EE)"

기타

  let df = DateFormatter()

//        df.dateFormat = "yyyy-MMMM"

        df.dateFormat = "yyyy. MM. dd(EE)"

        df.locale = Locale(identifier: "ko_KR")

7일전 날짜 저장

        let aWeekAgo : Double = Date().timeIntervalSince1970 - (7 * 60 * 60 * 24)

        GS.s.periodStartDate = Date(timeIntervalSince1970: aWeekAgo)

//----------------------

        let dt : Date = GS.s.periodStartDate ?? Date()

        let dateFormatter = DateFormatter()

        dateFormatter.timeZone = TimeZone(abbreviation: "KST")

        dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"

        dateLabel.text = dateFormatter.string(from: dt)

swift date to string