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）的数据帧：

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- 期间的总持续时间（长度） 23 03:15:00 至 2010-04-24 08:00:00.

棘手的部分是给定的长度可以运行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
2010-04-23 03:15:00 到 2010-04-24 08:00:00

我想使用 lubridate 并为每一行定义一个间隔，然后对持续时间求和，但我想不出来。

Answer 1

这是一个例子：

library(lubridate)

t0 <- as.POSIXct('2010-04-02 00:00:00')
t1 <- as.POSIXct('2010-04-21 09:00:00')

sum(dates$length[dates$start %within% interval(t0,t1)])
# [1] 13200

Answer 2

不确定具体问的是什么。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运行超过指定时间段结束的事件，而不是计算超过指定时间段结束的时间（反之亦然，开始时间在期开始）。例如，第 7 行运行远远超过 2010-04-21 09:00:00。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一个函数中。方法基本上是创建一个新的开始和结束，如果事件运行结束，它是指定间隔的边缘。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

Answer 3

另一种可能的解决方案可以通过使用 dplyr 中的 first 和 last 函数来实现。 first 和 last 函数将允许我们仅调整第一行和最后一行的长度 sum。

library(dplyr)
calculate_duration <- function(df, start_time, end_time){
  start_time <- as.POSIXct(start_time)
  end_time <- as.POSIXct(end_time)

  df %>% filter((start+length) >= start_time & start < end_time) %>%
    arrange(start) %>% 
    summarise(last_time = last(start) + last(length),
       first_time = first(start) + first(length),
       sum = sum(length) - 
       ifelse(last_time > end_time, 
             difftime(last_time, end_time, units = 'secs'), 0L) -
       ifelse(first(start) <  start_time, 
             difftime(start_time, first(start), units = 'secs'), 0L) ) %>%
    select(sum)

}

calculate_duration(dates,"2010-04-02 00:00:00", "2010-04-21 09:00:00")
#    sum
#1 12428

calculate_duration(dates,"2010-04-23 03:15:00", "2010-04-24 08:00:00")
#    sum
#1 10103


# Data

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))

计算给定时间段内时间间隔的持续时间

Calculate duration of a time interval within a given period

datatable

time

duration

r

lubridate