在 R (dplyr, r) 内分组、获取持续时间和设置条件

Question

我有一个数据集，df:（数据集包含 4000 多行）

  DATEB

  9/9/2019 7:51:58 PM
  9/9/2019 7:51:59 PM
  9/9/2019 7:51:59 PM
  9/9/2019 7:52:00 PM
  9/9/2019 7:52:01 PM
  9/9/2019 7:52:01 PM
  9/9/2019 7:52:02 PM
  9/9/2019 7:52:03 PM
  9/9/2019 7:54:00 PM
  9/9/2019 7:54:02 PM
  9/10/2019 8:00:00PM

如果日期时间之间的时间超过 120 秒，我想将它们放在不同的组中，并获取持续时间。

期望的输出：

Group   Duration

 a       5 sec
 b       2 sec
 c       0 sec




 dput:


  structure(list(DATEB = structure(c(2L, 3L, 3L, 4L, 5L, 5L, 6L, 
  7L, 8L, 9L, 1L), .Label = c("      9/10/2019 8:00:00 PM", "      9/9/2019 7:51:58 PM", 
  "      9/9/2019 7:51:59 PM", "      9/9/2019 7:52:00 PM", "      9/9/2019 7:52:01 PM", 
  "      9/9/2019 7:52:02 PM", "      9/9/2019 7:52:03 PM", "      9/9/2019 7:54:00 PM", 
  "      9/9/2019 7:54:02 PM"), class = "factor")), class = "data.frame", row.names = c(NA, 
  -11L))

我已经尝试了下面的代码，效果很好，但我希望 7:51:59 和 7:52:00 在同一组中。持续时间应该中断并创建新组的唯一时间是日期时间之间的时间超过 120 秒。

   df %>%
   mutate(DATEB = lubridate::mdy_hms(DATEB), 
   temp = floor_date(DATEB, "120 secs")) %>%
   group_by(temp) %>%
   summarise(duration = difftime(max(DATEB), min(DATEB), units = "secs"))

任何建议表示赞赏。

Answer 1

我们可以cut在这里使用：

library(dplyr)
df %>%
  mutate(DATEB = lubridate::mdy_hms(DATEB), 
        temp = cut(DATEB, breaks = "2 mins")) %>%
  group_by(temp) %>%
  summarise(duration = difftime(max(DATEB), min(DATEB), units = "secs"))

# A tibble: 3 x 2
#  temp                duration
#  <fct>               <drtn>  
#1 2019-09-09 19:51:00 5 secs  
#2 2019-09-09 19:53:00 2 secs  
#3 2019-09-10 19:59:00 0 secs