diff time r studio is not giving the outcome properly

Question

Im trying to calculate the difftime in minutes between two columns and the results seems to be not right.

BLOCK_DATE_TIME.x	a1_0	diff
2019-04-26 19:07:00	2019-04-27 09:00:00	773
2019-08-27 08:30:00	2019-08-27 09:00:00	-30

the code to calculate diff is the following:

test$diff <- difftime(test$a1_0,test$BLOCK_DATE_TIME.x,units = "mins")

The desire outcome is for the first line 833 and for the second 30.

Thanks in advance

Answer 1

It is possible that the columns are not Datetime class. If we convert to POSIXct, it works as expected

library(dplyr)
library(lubridate)
test1 <- test %>% 
      mutate(across(c(BLOCK_DATE_TIME.x, a1_0), ymd_hms),
         diff = difftime(a1_0, BLOCK_DATE_TIME.x, units = "mins"))
test1
#    BLOCK_DATE_TIME.x                a1_0     diff
#1 2019-04-26 19:07:00 2019-04-27 09:00:00 833 mins
#2 2019-08-27 08:30:00 2019-08-27 09:00:00  30 mins

data

test <- structure(list(BLOCK_DATE_TIME.x = c("2019-04-26 19:07:00", 
"2019-08-27 08:30:00"
), a1_0 = c("2019-04-27 09:00:00", "2019-08-27 09:00:00")), row.names = c(NA, 
-2L), class = "data.frame")