从 R 中的一个时间戳列创建开始时间和结束时间列

Question

我正在尝试确定事件（集群，1 或 2）何时开始和停止，因此我可以使用 timeDiff 并将 latlon 数据与这些停止/开始日期的天气数据相关联。 现在排除位置数据，我的数据看起来像这样（8000 多行，时间戳间隔 15 分钟，27 个唯一 ID，簇在 ID 内变化 50 多次）：

dput(head(mydata,80))structure(list(id = c(43486L, 43486L, 43486L, 43486L, 43486L, 
43486L, 43486L, 43486L, 43486L, 43486L, 43486L, 43486L, 43486L, 
43486L, 43486L, 43486L, 43486L, 43486L, 43486L, 43486L, 43486L, 
43486L, 43486L, 43486L, 43486L, 43486L, 43486L, 43486L, 43486L, 
43486L, 43486L, 43486L, 43486L, 43486L, 43486L, 43486L, 43486L, 
43486L, 43486L, 43486L, 43486L, 43486L, 43486L, 43486L, 43486L, 
43486L, 43486L, 43486L, 43486L, 43486L, 43486L, 43486L, 43486L, 
43486L, 43486L, 43486L, 43486L, 43486L, 43486L, 43486L, 43486L, 
43486L, 43486L, 43486L, 43486L, 43486L, 43486L, 43486L, 43486L, 
43486L, 43486L, 43486L, 43486L, 43486L, 43486L, 43486L, 43486L, 
43486L, 43486L, 43486L), cluster = structure(c(2L, 2L, 2L, 2L, 
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 1L, 2L, 
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L), .Label = c("1", 
"2"), class = "factor"), idswitch = c("43486 2 0", "43486 2 0", 
"43486 2 0", "43486 2 0", "43486 2 0", "43486 2 0", "43486 2 0", 
"43486 2 0", "43486 2 0", "43486 2 0", "43486 2 0", "43486 2 0", 
"43486 2 0", "43486 2 0", "43486 2 0", "43486 2 0", "43486 2 0", 
"43486 2 0", "43486 2 0", "43486 2 0", "43486 2 0", "43486 2 0", 
"43486 2 0", "43486 2 0", "43486 2 0", "43486 2 0", "43486 2 0", 
"43486 2 0", "43486 2 0", "43486 2 0", "43486 2 0", "43486 2 0", 
"43486 2 0", "43486 2 0", "43486 2 0", "43486 2 0", "43486 2 0", 
"43486 2 0", "43486 2 0", "43486 2 0", "43486 2 0", "43486 2 0", 
"43486 2 0", "43486 2 0", "43486 2 0", "43486 2 0", "43486 2 0", 
"43486 2 0", "43486 2 0", "43486 2 0", "43486 2 0", "43486 2 0", 
"43486 2 0", "43486 2 0", "43486 2 0", "43486 2 0", "43486 2 0", 
"43486 2 0", "43486 2 0", "43486 2 0", "43486 2 0", "43486 2 0", 
"43486 2 0", "43486 2 0", "43486 2 0", "43486 2 0", "43486 1 1", 
"43486 2 2", "43486 2 2", "43486 2 2", "43486 2 2", "43486 2 2", 
"43486 2 2", "43486 2 2", "43486 2 2", "43486 2 2", "43486 2 2", 
"43486 2 2", "43486 2 2", "43486 2 2"), t_ = structure(c(1661663122, 
1661664035, 1661664948, 1661665900, 1661666812, 1661667724, 1661668637, 
1661669550, 1661670463, 1661671376, 1661672289, 1661673202, 1661674114, 
1661675026, 1661675939, 1661676852, 1661677764, 1661678676, 1661679588, 
1661680501, 1661681414, 1661682326, 1661683239, 1661684151, 1661685063, 
1661685975, 1661686888, 1661687800, 1661688712, 1661689624, 1661690536, 
1661691449, 1661692362, 1661693275, 1661694187, 1661695099, 1661696011, 
1661696923, 1661697835, 1661698747, 1661699659, 1661700571, 1661701483, 
1661702976, 1661703888, 1661704800, 1661705714, 1661706626, 1661707541, 
1661708454, 1661709366, 1661710279, 1661711191, 1661712104, 1661713017, 
1661713930, 1661714842, 1661715755, 1661716669, 1661717583, 1661718496, 
1661719410, 1661720324, 1661721236, 1661722149, 1661723061, 1661723973, 
1661724885, 1661725798, 1661726713, 1661727629, 1661728542, 1661729454, 
1661730370, 1661731283, 1661732196, 1661733109, 1661734022, 1661734934, 
1661735848), tzone = "", class = c("POSIXct", "POSIXt")), mode.switches = c(0, 
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 
0, 0, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2)), row.names = c(NA, 
-80L), class = c("tbl_df", "tbl", "data.frame"))

这是一个（稍微修改过的）块来说明我的问题：

id cluster idswitch  t_                  mode.switches
   <int> <fct>   <chr>     <dttm>                      <dbl>
 1 43486 2       43486 2 0 2022-08-28 00:05:22             0
 2 43486 2       43486 2 0 2022-08-28 00:20:35             0
 3 43486 2       43486 2 0 2022-08-28 00:35:48             0
 4 43486 2       43486 2 0 2022-08-28 00:51:40             0
 5 43486 2       43486 2 0 2022-08-28 01:06:52             0
 6 43486 1       43486 2 0 2022-08-28 01:22:04             0

我想要一个如下所示的 output：

idcluster   StartTime           EndTime  
\<chr\>      \<dttm\>              \<dttm\>  
1 43486 2 2022-08-28 00:05:22 2022-08-28 01:22:04  
2 43486 1 2022-08-28 01:22:04 2022-08-28 01:37:17
3 43486 2 2022-08-28 01:37:17 2022-08-28 02:07:43
4 43486 1 2022-08-28 02:07:43 2022-08-31 19:29:55

事件 2 在事件 1 开始的同时结束。

我使用 paste 将 id 和 cluster 归为一列，并创建了一个新的 col，mode.switches，它总结了每个 id 事件变化的次数，认为这可能有帮助（剧透，事实并非如此）。 我的一些尝试如下：

mydata <- mydata %>%
  group_by(id) %>%
  mutate(mode.switches = cumsum(c(0,as.numeric(diff(cluster))!=0))) %>%
  ungroup()

#First try---------
test <- all %>% 
  group_by(idswitch) %>%
  summarise(
    first = min(t_), 
    last = max(t_)
  )

#This is not what I want. An event stops and starts at the same time, and start/end times are wrong. Events  need to start when the event before them stops.
   idswitch   first               last               
   <chr>      <dttm>              <dttm>             
 1 43486 1 1  2022-08-28 16:59:33 2022-08-28 16:59:33
 2 43486 1 11 2022-08-30 14:12:25 2022-08-30 20:47:56
 3 43486 1 13 2022-08-30 21:18:20 2022-08-30 23:04:47
 4 43486 1 15 2022-08-31 14:40:47 2022-08-31 19:29:55
 5 43486 1 17 2022-08-31 20:00:22 2022-08-31 21:46:53

#lead/lag - it still respects idcluster so won't use t_ +1 or -1 of another idcluster, but I need the times related to id and cluster....---------
test2 <- mydata %>%
  group_by(idcluster) %>%
  mutate(start=t_, stop=lead(t_, n=1))
sum(is.na(test$stop)) #606 NAs :(

#same problems------------------
test7<- all %>%
  filter(cluster == "1" | lag(cluster) == "1") %>%
  group_by(mode.switches, id, cluster, gr = cumsum(lag(cluster != "1", default = TRUE))) %>%
  summarise(StartTime = first(t_), 
            EndTime = last(t_)) %>%
  mutate(EndTime = replace(EndTime, StartTime == EndTime, NA)) %>%
  dplyr::select(-gr)
sum(is.na(test7$EndTime)) #378 NAs, lame.

存在很多类似的问题，但似乎没有一个能解决我的问题： Identify start and stop sequences and length of run in R Create start and end time column from a single datetime column in R R Start Column & End Column Time Log Obtaining the start and单列数据的结束日期如何使用lubridate从R的大型数据集中的单列中提取开始和结束日期？ R 尝试从单列创建开始和停止时间根据 R 中的多个条件创建开始和结束时间列（dplyr、lubridate）

Answer 1

感谢您添加数据。

您可以先group_by id 。 然后， filter并保留给定id的第一行，或者cluster发生变化的地方。

然后，您可以添加一个end列，它是时间的后续行lead值。

library(dplyr)

df %>% 
  group_by(id) %>% 
  filter(row_number() == 1 | cluster != lag(cluster)) %>%
  mutate(end = lead(t_))

Output

     id cluster idswitch  t_                  mode.switches end                
  <int> <fct>   <chr>     <dttm>                      <dbl> <dttm>             
1 43486 2       43486 2 0 2022-08-28 01:05:22             0 2022-08-28 17:59:33
2 43486 1       43486 1 1 2022-08-28 17:59:33             1 2022-08-28 18:14:45
3 43486 2       43486 2 2 2022-08-28 18:14:45             2 NA