如何在swift中格式化用户显示(社交网络)的时间间隔？

Question

我有一个时间间隔,比如12600,相当于3小时30分钟.我如何格式化任何这样的时间间隔,以便只保留间隔的最高部分(例如在这种情况下图中,小时),并将正确的区域设置缩写附加到数字上.例如10米(10分钟),3d(3天),1年(1年).

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编辑:以下是一些例子:

Time interval in: 90000    Whole string: 1d      String out: 1d
Time interval in: 900      Whole string: 15m     String out: 15m
Time interval in: 13500    Whole String: 3h 45m  String out: 4h

作为一般规则,应用正常的舍入规则(向下舍入3.4轮,向上舍入3.6轮).

Answer 1

使用DateComponentFormatter,自iOS 8起可用:

func format(duration: TimeInterval) -> String {
    let formatter = DateComponentsFormatter()
    formatter.allowedUnits = [.day, .hour, .minute, .second]
    formatter.unitsStyle = .abbreviated
    formatter.maximumUnitCount = 1

    return formatter.string(from: duration)!
}

for d in [12600.0, 90000.0, 900.0, 13500.0] {
    let str = format(duration: d)
    print("\(d): \(str)")
}

这打印:

12600.0: 4h
90000.0: 1d
900.0: 15m
13500.0: 4h

Answer 2

Swift 3扩展:

extension TimeInterval {

  func format() -> String? {
    let formatter = DateComponentsFormatter()
    formatter.allowedUnits = [.day, .hour, .minute, .second, .nanosecond]
    formatter.unitsStyle = .abbreviated
    formatter.maximumUnitCount = 1
    return formatter.string(from: self)
  }
}

Answer 3

以防万一有人想要。.Swift 4

extension TimeInterval {
    func format(using units: NSCalendar.Unit) -> String? {
        let formatter = DateComponentsFormatter()
        formatter.allowedUnits = units
        formatter.unitsStyle = .abbreviated
        formatter.zeroFormattingBehavior = .pad

        return formatter.string(from: self)
    }
}

用法示例：

let value:TimeInterval =  12600.0
print("\(value.format(using: [.hour, .minute, .second])!)")

结果将是：

3h 30m 0s