如何在swift中获得本周的开始和结束？

参见英文答案 > How do I find the beginning of the week from an NSDate?                                    4个
>             How to get Monday’s date of the current week in swift                                    7个
如何在swift中获得本周的开始和结束？
这是我的代码

extension Date {
    var startOfWeek: Date? {
        let gregorian = Calendar(identifier: .gregorian)
        guard let sunday = gregorian.date(from: gregorian.dateComponents([.yearForWeekOfYear, .weekOfYear], from: self)) else { return nil }
        return gregorian.date(byAdding: .day, value: 1, to: sunday)
    }

    var endOfWeek: Date? {
        let gregorian = Calendar(identifier: .gregorian)
        guard let sunday = gregorian.date(from: gregorian.dateComponents([.yearForWeekOfYear, .weekOfYear], from: self)) else { return nil }
        return gregorian.date(byAdding: .day, value: 7, to: sunday)
    }
}

我这样打电话

let startWeek = Date().startOfWeek
let endWeek = Date().endOfWeek
print(startWeek!)
print(endWeek!)
var dateFormat1 = DateFormatter()
dateFormat1.dateFormat = "dd-MM-yy"
let startWeek2 = dateFormat1.string(from: startWeek!)
var dateFormat12 = DateFormatter()
dateFormat12.dateFormat = "dd-MM-yy"
let endWeek2 = dateFormat12.string(from: endWeek!)
print(startWeek2)
print(endWeek2)

和输出

2017-09-24 18:30:00 +0000
2017-09-30 18:30:00 +0000
25-09-17
01-10-17

你的代码工作得非常好.如果要在Playground中运行代码,则可以看到实际的Date对象而不是String表示.即使您没有指定DateFormatter,在执行print(Date())时,Swift使用DateFormatter来打印Date对象,因此该值将是相对时间而不是由提供的绝对时间点.日期对象.

在游乐场中,您可以看到实际的startOfWeek是“2017年9月25日上午12:00”,而endOfWeek是“2017年10月1日上午12:00”,这是本周的正确值.

不要使用print(Date())来检查Date对象的正确性,因为正如您所看到的,由于使用了基础DateFormatters,它将产生意外结果.