Swift - 打印今年的当前星期几

Question

我需要一种方法来打印今年到目前为止的周数。
我已经成功打印了天数和月数(参见下面的代码)。
但无法弄清楚如何在总周数内执行相同的操作。

今年迄今为止的总天数:

let dateDay = Date()
                        let dateFormatterDay = DateFormatter()
                        dateFormatterDay.dateFormat = "DD"
                        let dateByDay = dateFormatterDay.string(from: dateDay)
                        print(dateByDay)

今年迄今为止的总月份:

 let dateMonth = Date()
                        let dateFormatterMonth = DateFormatter()
                        dateFormatterMonth.dateFormat = "MM"
                        let dateByMonth = dateFormatterMonth.string(from: dateMonth)
                        print(dateByMonth)

Answer 1

尝试以下代码片段。它是用 Swift 4 和 Swift 5 编写的。

let currentDate = Date() 
print(currentDate.dayOfYear)   // Day of Year
print(currentDate.weekOfYear)  // Week of Year
print(currentDate.monthOfYear) // Month of Year

这将分别打印一年中的总天数、周数和月份数。

extension Date {
    public var dayOfYear: Int {
        return Calendar.current.ordinality(of: .day, in: .year, for: self)!
    }
    public var weekOfYear: Int {
        return Calendar.current.ordinality(of: .weekOfYear, in: .year, for: self)!
    }
    public var monthOfYear: Int {
        return Calendar.current.ordinality(of: .month, in: .year, for: self)!
    }
}