我正在尝试计算我的电子邮件持续时间。我有按分组的电子邮件ID。在此示例中，我已经按组A对电子邮件进行了分组。我希望计算A组的电子邮件阅读持续时间。我当前使用的代码以秒为单位计算其上一次和第一次。
data <-rawdata %>%
group_by(ID) %>%
summarize(diff = difftime(last(as.POSIXct(Endtime, format ="%m/%d/%Y %I:%M:%S %p")),
first(as.POSIXct(Starttime, format = "%m/%d/%Y %I:%M:%S %p" )), units = "secs"))
但是，我认为这不是我邮件阅读的准确显示。总的来说，我希望每行的时差可以更准确地读取。期望的输出将是（以下），因为它显示了每一行的时差，使我可以进一步求和整个diff列，以确定我的电子邮件持续时间（以秒为单位）。
Starttime Endtime ID diff
12/18/2019 4:06:59PM 12/18/2019 4:07:05 PM A 6 secs
12/18/2019 4:07:26PM 12/18/2019 4:07:28 PM A 1 secs
12/17/2019 6:48:06PM 12/17/2019 6:48:07PM A 1 sec
12/17/2019 6:25:16PM 12/17/2019 6:25:22PM A 6 secs
感谢您的帮助。我将继续对此进行研究！塔尼莎·哈德森
如果您希望阅读电子邮件的开始时间和结束时间有所不同，可以执行
library(dplyr)
rawdata %>%
mutate_at(vars(ends_with('time')), lubridate::mdy_hms) %>%
mutate(diff = difftime(Endtime, Starttime, units = "secs"))
# Starttime Endtime ID diff
#1 2019-12-18 16:06:59 2019-12-18 16:07:05 A 6 secs
#2 2019-12-18 16:07:26 2019-12-18 16:07:28 A 2 secs
#3 2019-12-17 18:48:06 2019-12-17 18:48:07 A 1 secs
#4 2019-12-17 18:25:16 2019-12-17 18:25:22 A 6 secs
或在基数R中：
transform(transform(rawdata,
Starttime = as.POSIXct(Starttime, format = "%m/%d/%Y %I:%M:%S %p"),
Endtime = as.POSIXct(Endtime, format = "%m/%d/%Y %I:%M:%S %p")),
diff = difftime(Endtime, Starttime, units = "secs"))
数据
rawdata <- structure(list(Starttime = structure(c(3L, 4L, 2L, 1L),
.Label = c("12/17/2019 6:25:16PM", "12/17/2019 6:48:06PM", "12/18/2019 4:06:59PM",
"12/18/2019 4:07:26PM"), class = "factor"), Endtime = structure(c(3L, 4L, 2L, 1L),
.Label = c("12/17/2019 6:25:22PM", "12/17/2019 6:48:07PM", "12/18/2019 4:07:05 PM",
"12/18/2019 4:07:28 PM"), class = "factor"), ID = structure(c(1L, 1L, 1L, 1L),
.Label = "A", class = "factor")), row.names = c(NA, -4L), class = "data.frame")