How to add a new column to express results between "Start time" in the next row minus &quo-CodePudding

How to add a new column to express results between "Start time" in the next row minus "End time" in the previous row? Thank you very much

CodePudding user response：

You can try sapply.

dat$result <- c( sapply( 2:nrow(dat), function(x) 
                   dat$start_time[x] - dat$end_time[(x-1)] ), NA )

dat
            start_time            end_time   result
1  2021-11-09 00:19:15 2021-11-03 05:51:58 5.772245
2  2021-11-09 00:24:00 2021-11-03 07:26:37 5.674387
3  2021-11-08 23:37:44 2021-11-03 05:36:39 5.710625
4  2021-11-08 22:39:57 2021-11-03 05:57:00 5.677801
5  2021-11-08 22:13:02 2021-11-03 07:35:49 5.617558
6  2021-11-08 22:25:06 2021-11-03 06:05:02 5.680220
7  2021-11-08 22:24:33 2021-11-03 07:20:53 5.678322
8  2021-11-08 23:37:40 2021-11-03 05:05:11 5.814352
9  2021-11-09 00:37:51 2021-11-03 06:44:09 5.692847
10 2021-11-08 23:21:51 2021-11-03 05:17:13       NA

Data:

dat <- structure(list(start_time = structure(c(1636413555.55965, 1636413840.55965,
1636411064.55965, 1636407597.55965, 1636405982.55965, 1636406706.55965,
1636406673.55965, 1636411060.55965, 1636414671.55965, 1636410111.55965
), class = c("POSIXct", "POSIXt")), end_time = structure(c(1635915118.55965,
1635920797.55965, 1635914199.55965, 1635915420.55965, 1635921349.55965,
1635915902.55965, 1635920453.55965, 1635912311.55965, 1635918249.55965,
1635913033.55965), class = c("POSIXct", "POSIXt"))), row.names = c(NA,
-10L), class = "data.frame")

CodePudding user response：

Assuming your start and end time are date objects you can simply do

library(tidyverse)
dat %>%
  mutate(diff = lead(start_time) - end_time)