r - 计算给定时间段内时间间隔的持续时间

Question

我有一个包含开始时间和长度(以秒为单位)的数据框:

dates<-data.frame(start=as.POSIXct(c("2010-04-03 03:02:38 UTC","2010-04-03 06:03:14 UTC","2010-04-20 03:05:52 UTC","2010-04-20 03:17:42 UTC","2010-04-21 03:09:38 UTC","2010-04-21 07:10:14 UTC","2010-04-21 08:12:52 UTC","2010-04-23 03:13:42 UTC","2010-04-23 03:25:42 UTC","2010-04-23 03:36:38 UTC","2010-04-23 08:58:14 UTC","2010-04-24 03:21:52 UTC","2010-04-24 03:22:42 UTC","2010-04-24 07:24:19 UTC","2010-04-24 07:55:19 UTC")),length=c(3600,300,900,3600,300,900,3600,300,900,3600,300,900,3600,300,900))

> dates
                 start length
1  2010-04-03 03:02:38   3600
2  2010-04-03 06:03:14    300
3  2010-04-20 03:05:52    900
4  2010-04-20 03:17:42   3600
5  2010-04-21 03:09:38    300
6  2010-04-21 07:10:14    900
7  2010-04-21 08:12:52   3600
8  2010-04-23 03:13:42    300
9  2010-04-23 03:25:42    900
10 2010-04-23 03:36:38   3600
11 2010-04-23 08:58:14    300
12 2010-04-24 03:21:52    900
13 2010-04-24 03:22:42   3600
14 2010-04-24 07:24:19    300
15 2010-04-24 07:55:19    900

我需要找到从 2010-04-02 00:00:00 到 2010-04-21 09:00:00 期间以及从 2010-04-23 03 期间的总持续时间(长度) :15:00 至 2010-04-24 08:00:00.

棘手的部分是给定的长度可以超过指定时间段的末尾，我不想计算那个额外的持续时间。

我希望得到:

• 2010-04-02 00:00:00 到 2010-04-21 09:00:00 为 12428 秒
• 2010-04-23 03:15:00 到 2010-04-24 08:00:00 为 10103 秒

我正在考虑使用 lubridate 并为每一行定义一个间隔，然后对持续时间求和，但我无法弄清楚。

Answer 1

不确定到底在问什么。另一个答案只是对指定时间间隔内的开始时间求和 length 。但是，我将这个问题解释为想要处理长度可能超过指定期间结束的事件，而不是计算超过指定期间结束的时间(反之亦然，对于期间开始之前的开始时间).例如，第 7 行在 2010-04-21 09:00:00 之后运行。这就是提供预期输出很有帮助的原因!

无论如何，这里有一种方法可以执行我认为您的意思是包装在函数中的操作。方法基本上是创建一个新的开始和结束，如果事件结束，这是指定间隔的边缘。我可能遗漏了一些边缘情况，欢迎改进!

dates<-data.frame(start=as.POSIXct(c("2010-04-03 03:02:38 UTC","2010-04-03 06:03:14 UTC","2010-04-20 03:05:52 UTC","2010-04-20 03:17:42 UTC","2010-04-21 03:09:38 UTC","2010-04-21 07:10:14 UTC","2010-04-21 08:12:52 UTC","2010-04-23 03:13:42 UTC","2010-04-23 03:25:42 UTC","2010-04-23 03:36:38 UTC","2010-04-23 08:58:14 UTC","2010-04-24 03:21:52 UTC","2010-04-24 03:22:42 UTC","2010-04-24 07:24:19 UTC","2010-04-24 07:55:19 UTC")),length=c(3600,300,900,3600,300,900,3600,300,900,3600,300,900,3600,300,900))
library(dplyr)
library(lubridate)

length_within <- function(tbl, interval_start, interval_end){
  intv_start = as.POSIXct(interval_start)
  intv_end = as.POSIXct(interval_end)
  tbl %>%
    mutate(
      end = start + length,
      counted_start = ifelse(start < intv_start, intv_start, start),
      counted_end = ifelse(end > intv_end, intv_end, end),
      seconds = counted_end - counted_start
    ) %>%
    filter(seconds >= 0) %>%
    summarise(total = sum(seconds)) %>%
    `[[` (1)
}

length_within(dates,"2010-04-02 00:00:00", "2010-04-21 09:00:00")
#> [1] 12428
length_within(dates,"2010-04-23 03:15:00", "2010-04-24 08:00:00")
#> [1] 10103