只比较Date对象中的时间差

Question

我有两个Date对象，我只想比较它们之间的时间差，忽略日期。可能类似于：

dt1=(日期(2016-09-22 20:05:01 UTC
dt2=(日期(2016-08-20 22:06:00 UTC

并且dt1和dt2之间的差将是2小时或121分钟。

Swift中有我可以做到的功能吗？

Answer 1

您可以使用Calendar提取DateComponents，然后将其中的天、月和年与另一个的小时、分钟和秒组合到另一个Date对象中。然后，您可以使用有据可查的方法来比较共享同一日期的两个Date对象。

例如，给定date1和date2，我们可以用date1的日期而不是date2的时间来计算date3。然后我们可以将date1与这个新的date3:进行比较

let calendar = Calendar.current
let components2 = calendar.dateComponents([.hour, .minute, .second], from: date2)
let date3 = calendar.date(bySettingHour: components2.hour!, minute: components2.minute!, second: components2.second!, of: date1)!

然后，为了获得date1和date3之间的分钟数：

let minutes = calendar.dateComponents([.minute], from: date1, to: date3).minute!

或小时和分钟：

let difference = calendar.dateComponents([.hour, .minute], from: date1, to: date3)
let hours = difference.hour!
let minutes = difference.minute!

或者，如果你想向用户展示这一点，你通常会使用DateComponentsFormatter来获得一个很好的本地化字符串表示：

let formatter = DateComponentsFormatter()
formatter.unitsStyle = .full
formatter.allowedUnits = [.hour, .minute]  // or [.minute]
let string = formatter.string(from: date1, to: date3)!

Answer 2

忽略日期，您可以使用timeIntervalSince(date:(来获取两个日期之间的秒数。

Answer 3

使用NSCalenar，然后找出小时、分钟，然后找出它们之间的差异。

Answer 4

Swift 3扩展，用于比较仅时间

import UIKit
extension Date {
    func compareTimeOnly(to: Date) -> ComparisonResult {
    let calendar = Calendar.current
    let components2 = calendar.dateComponents([.hour, .minute, .second], from: to)
    let date3 = calendar.date(bySettingHour: components2.hour!, minute: components2.minute!, second: components2.second!, of: self)!
    let seconds = calendar.dateComponents([.second], from: self, to: date3).second!
    if seconds == 0 {
        return .orderedSame
    } else if seconds > 0 {
        // Ascending means before
        return .orderedAscending
    } else {
        // Descending means after
        return .orderedDescending
    }
    }
}

一些测试

let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss"
let date1 = Date()
var date2 = dateFormatter.date(from: "2016-12-26T12:12:12")!
let result = date1.compareTimeOnly(to: date2)
print(result.rawValue)

Answer 5

func findsecond(s_date:String,e_date:String) -> Int {
    //set date formate
    let Dateformatter = DateFormatter()
    Dateformatter.dateFormat = "dd MMM yyyy h:mm a"
    //convert string to date
    let dateold = Dateformatter.date(from: start_date)!
    let datenew = Dateformatter.date(from: end_date)!
    //use default datecomponents with two dates
    let calendar1 = Calendar.current
    let components = calendar1.dateComponents([.second], from: dateold, to: datenew)
    let seconds = components.second
    print("Seconds: (seconds)")
    return seconds!
}