Question

NSDate/NSCalendar是否有任何方法可以计算当月和当年的天数？

我唯一看到的是从给定日期或两个日期之间获得的天数这是唯一的方法吗？

Answer 1

这是一种适用于月份和年份的方法：

let calendar = NSCalendar.currentCalendar()
let date = NSDate()

// Calculate start and end of the current year (or month with `.Month`):
var startOfInterval : NSDate?
var lengthOfInterval = NSTimeInterval()
calendar.rangeOfUnit(.Year, startDate: &startOfInterval, interval: &lengthOfInterval, forDate: date)
let endOfInterval = startOfInterval!.dateByAddingTimeInterval(lengthOfInterval)

// Compute difference in days:
let days = calendar.components(.Day, fromDate: startOfInterval!, toDate: endOfInterval, options: [])
print(days)

（您可能希望添加一些错误检查而不是强行解包自选。）

更新 Swift 3：

let calendar = Calendar.current
let date = Date()

// Calculate start and end of the current year (or month with `.month`):
let interval = calendar.dateInterval(of: .year, for: date)!

// Compute difference in days:
let days = calendar.dateComponents([.day], from: interval.start, to: interval.end).day!
print(days)

Answer 2

let date = NSDate()
let cal = NSCalendar(calendarIdentifier:NSCalendarIdentifierGregorian)!
let days = cal.rangeOfUnit(.Day, inUnit: .Month, forDate: date)

print("\(days) in the month of \(date)")

如何计算当月/年的天数

2 个答案: