如何获取当月的最后日期

Question

我花了差不多一个星期尝试不成功.如何获取当月的最后日期.例如,如果它是非闰年的二月,那么该月的最后一个日期必须是28.如何获得'28'.另一个例子:如果是1月那么最后一个日期必须是'31'

Answer 1

有很多方法,这里有两个:

获取下一个1.并减去一天

func lastDayOfMonth1() -> Date
{
   let calendar = Calendar.current
   let components = DateComponents(day:1)
   let startOfNextMonth = calendar.nextDate(after:Date(), matching: components, matchingPolicy: .nextTime)!
   return calendar.date(byAdding:.day, value: -1, to: startOfNextMonth)!
}

print(lastDayOfMonth1())

用于range(of:in:for:)从范围中获取最后一天并相应地设置组件:

func lastDayOfMonth2() -> Date
{
    let calendar = Calendar.current
    let now = Date()
    var components = calendar.dateComponents([.year, .month, .day], from: now)
    let range = calendar.range(of: .day, in: .month, for: now)!
    components.day = range.upperBound - 1
    return calendar.date(from: components)!
}

print(lastDayOfMonth2())