Question

我在String中创建了created_at（以2015-12-16 19:28:16的形式）。我想将其与当前时间进行比较，并以5h，35m，3d等形式给出时差...

我在SO answer找到了我可以使用扩展来实现这一点。这是扩展名：

extension NSDate {
    func yearsFrom(date:NSDate) -> Int{
        return NSCalendar.currentCalendar().components(.Year, fromDate: date, toDate: self, options: []).year
    }
    func monthsFrom(date:NSDate) -> Int{
        return NSCalendar.currentCalendar().components(.Month, fromDate: date, toDate: self, options: []).month
    }
    func weeksFrom(date:NSDate) -> Int{
        return NSCalendar.currentCalendar().components(.WeekOfYear, fromDate: date, toDate: self, options: []).weekOfYear
    }
    func daysFrom(date:NSDate) -> Int{
        return NSCalendar.currentCalendar().components(.Day, fromDate: date, toDate: self, options: []).day
    }
    func hoursFrom(date:NSDate) -> Int{
        return NSCalendar.currentCalendar().components(.Hour, fromDate: date, toDate: self, options: []).hour
    }
    func minutesFrom(date:NSDate) -> Int{
        return NSCalendar.currentCalendar().components(.Minute, fromDate: date, toDate: self, options: []).minute
    }
    func secondsFrom(date:NSDate) -> Int{
        return NSCalendar.currentCalendar().components(.Second, fromDate: date, toDate: self, options: []).second
    }
    func offsetFrom(date:NSDate) -> String {
        if yearsFrom(date)   > 0 { return "\(yearsFrom(date))y"   }
        if monthsFrom(date)  > 0 { return "\(monthsFrom(date))M"  }
        if weeksFrom(date)   > 0 { return "\(weeksFrom(date))w"   }
        if daysFrom(date)    > 0 { return "\(daysFrom(date))d"    }
        if hoursFrom(date)   > 0 { return "\(hoursFrom(date))h"   }
        if minutesFrom(date) > 0 { return "\(minutesFrom(date))m" }
        if secondsFrom(date) > 0 { return "\(secondsFrom(date))s" }
        return ""
    }
}

所以我可以使用dateWithEra()并致电offsetFrom()：

let date4 = NSCalendar.currentCalendar().dateWithEra(1, year: 2015, month: 11, day: 28, hour: 5, minute: 9, second: 0, nanosecond: 0)!

let timeOffset3 = NSDate().offsetFrom(date3) // "54m"

但是，我想在String中给它一个日期。

let myDate = post!["created_at"].string! // 2015-12-16 19:28:16

如何为其提供字符串以便能够转换3h，30m？我想我可以利用字符串并将其放在dateWithEra中，但有没有办法直接给它一个字符串？

还是我完全没法了？我想要实现的是获取字符串中的日期（2015-12-16 19:28:16格式）与当前时间之间的时差，并将其显示为"5h"或"50m"。< / p>

Answer 1

要从格式化字符串中获取NSDate，请使用NSDateFormatter

let dateString = "2015-12-16 19:28:16"
let inputFormatter = NSDateFormatter()
inputFormatter.dateFormat = "YYYY-MM-dd HH:mm:ss"
let date = inputFormatter.dateFromString(dateString)!

如果您可以使用min代替m获取某些本地化中的分钟缩写，最简单的方法是NSDateComponentsFormatter

let outputformatter = NSDateComponentsFormatter()
outputformatter.allowedUnits = [.Day, .Hour, .Minute, .Second]
outputformatter.unitsStyle = .Abbreviated
let timeOffset = outputformatter.stringFromDate(date, toDate: NSDate())!

修改：

要始终m而不是min，请timeOffset变为可变并添加

var timeOffset = outputformatter.stringFromDate(date, toDate: NSDate())!
if let minRange = timeOffset.rangeOfString("in") {
    timeOffset = timeOffset.substringToIndex(minRange.startIndex) + timeOffset.substringFromIndex(minRange.endIndex)
}

与当前时间的差异 - 使用String而不是dateWithEra

1 个答案: