swift get day from available date code example

Example 1: get day start time in swift

extension Date {

    var startOfDay : Date {
        let calendar = Calendar.current
        let unitFlags = Set<Calendar.Component>([.year, .month, .day])
        let components = calendar.dateComponents(unitFlags, from: self)
        return calendar.date(from: components)!
   }

    var endOfDay : Date {
        var components = DateComponents()
        components.day = 1
        let date = Calendar.current.date(byAdding: components, to: self.startOfDay)
        return (date?.addingTimeInterval(-1))!
    }
}
//Usage:

    let myDate = Date()
    let startOfDate = myDate.startOfDay
    let endOfDate = myDate.endOfDay

Example 2: swift 5 only the day number from date

let dateString = "2018-12-24 18:00:00 UTC"
    let formatter = DateFormatter()
    formatter.dateFormat = "yyyy-MM-dd HH:mm:ss 'UTC'"
    guard let date = formatter.date(from: dateString) else {
        return
    }

    formatter.dateFormat = "yyyy"
    let year = formatter.string(from: date)
    formatter.dateFormat = "MM"
    let month = formatter.string(from: date)
    formatter.dateFormat = "dd"
    let day = formatter.string(from: date)
    print(year, month, day) // 2018 12 24