swift当月的第一天和最后一天 [英] first and last day of the current month in swift

问题描述

我正试图在swift中获得本月的第一天和最后一天。

I'm trying to get the first and last day of the month in swift.

到目前为止，我有以下内容：

So far I have the following:

let dateFormatter = NSDateFormatter()
let date = NSDate()
dateFormatter.dateFormat = "yyyy-MM-dd"
let calendar = NSCalendar.currentCalendar()
let components = calendar.components([.Year, .Month, .Day, .Hour, .Minute, .Second], fromDate: date)

let month = components.month
let year = components.year

let startOfMonth = ("\(year)-\(month)-01")

但我不知道如何获得最后约会。有缺点的内置方法吗？显然它必须考虑到闰年等。

But I'm not sure how to get the last date. Is there a built in method I'm missing? Obviously it has to take into account leap years etc.

推荐答案

你只需

let components = calendar.components([.Year, .Month], fromDate: date)
let startOfMonth = calendar.dateFromComponents(components)!
print(dateFormatter.stringFromDate(startOfMonth)) // 2015-11-01

To获取一个月的最后一天，添加一个月并减去一天：

To get the last day of the month, add one month and subtract one day:

let comps2 = NSDateComponents()
comps2.month = 1
comps2.day = -1
let endOfMonth = calendar.dateByAddingComponents(comps2, toDate: startOfMonth, options: [])!
print(dateFormatter.stringFromDate(endOfMonth)) // 2015-11-30

或者，使用 rangeOfUnit 方法，该方法为您提供
的开头和月长：

Alternatively, use the rangeOfUnit method which gives you the start and the length of the month:

var startOfMonth : NSDate?
var lengthOfMonth : NSTimeInterval = 0
calendar.rangeOfUnit(.Month, startDate: &startOfMonth, interval: &lengthOfMonth, forDate: date)

对于月份最后一天的日期，请添加月份减去一秒的长度：

For a date on the last day of month, add the length of the month minus one second:

let endOfMonth = startOfMonth!.dateByAddingTimeInterval(lengthOfMonth - 1)

这篇关于swift当月的第一天和最后一天的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！