I would like to create multiple variables to show the time differences from a variable (V0) for several variables. I would like the absolute difference (i.e., ignoring the sign of the difference). All my variables are in date format.
I have the below code, which works, but I imagine there is a neater/better way of doing this in fewer lines of code. I've tried a couple of things without much luck.
df$V1_timediff <- (abs(as.numeric(difftime(df$V0, df$V1, units = "days"))))
df$V2_timediff <- (abs(as.numeric(difftime(df$V0, df$V2, units = "days"))))
df$V3_timediff <- (abs(as.numeric(difftime(df$V0, df$V3, units = "days"))))
df$V4_timediff <- (abs(as.numeric(difftime(df$V0, df$V4, units = "days"))))
I'll demonstrate using mtcars. Since it doesn't have POSIXt objects, I'll use simple -; this should work for your case as well, no changes, so technically no need for difftime, the results should be identical. However, the premise of both solutions below will work if adapted to use difftime.
library(dplyr)
mtcars %>%
mutate(across(vs:carb, list(timediff = ~ abs(as.numeric(cyl - ., units = "days"))))) %>%
head()
# mpg cyl disp hp drat wt qsec vs am gear carb vs_timediff am_timediff gear_timediff carb_timediff
# Mazda RX4 21.0 6 160 110 3.90 2.620 16.46 0 1 4 4 6 5 2 2
# Mazda RX4 Wag 21.0 6 160 110 3.90 2.875 17.02 0 1 4 4 6 5 2 2
# Datsun 710 22.8 4 108 93 3.85 2.320 18.61 1 1 4 1 3 3 0 3
# Hornet 4 Drive 21.4 6 258 110 3.08 3.215 19.44 1 0 3 1 5 6 3 5
# Hornet Sportabout 18.7 8 360 175 3.15 3.440 17.02 0 0 3 2 8 8 5 6
# Valiant 18.1 6 225 105 2.76 3.460 20.22 1 0 3 1 5 6 3 5
tmp <- lapply(mtcars$cyl - subset(mtcars, select = vs:carb),
function(z) abs(as.numeric(z, units = "days")))
names(tmp) <- paste0(names(tmp), "_timediff")
head(cbind(mtcars, tmp))
# mpg cyl disp hp drat wt qsec vs am gear carb vs_timediff am_timediff gear_timediff carb_timediff
# Mazda RX4 21.0 6 160 110 3.90 2.620 16.46 0 1 4 4 6 5 2 2
# Mazda RX4 Wag 21.0 6 160 110 3.90 2.875 17.02 0 1 4 4 6 5 2 2
# Datsun 710 22.8 4 108 93 3.85 2.320 18.61 1 1 4 1 3 3 0 3
# Hornet 4 Drive 21.4 6 258 110 3.08 3.215 19.44 1 0 3 1 5 6 3 5
# Hornet Sportabout 18.7 8 360 175 3.15 3.440 17.02 0 0 3 2 8 8 5 6
# Valiant 18.1 6 225 105 2.76 3.460 20.22 1 0 3 1 5 6 3 5