Hello to everyone, Let's consider, just by way of example, the following date
and data table: opening <- as.Date("1990-01-01")DT <- data.table(ID=c(1,2,3),
start=c("1985-01-01","1993-07-15","1993-05-17"),
end=c("1992-05-01","1997-02-25","2002-01-01"), value=c(7.8, 3.2, 20.0))
FIRST QUESTION: If I execute: DTNEW <- DT[ , { if (all(start <= opening)){
result <- list(start, end, t.dif= unclass(round(difftime(end,
start)/365.25,1)), value) } else { result <- list(start, end, t.dif=
20, value) } result}, by=ID] Why can I not keep the column names? ID
t.dif 1: 1 1985-01-01 1992-05-01 7.3 7.82: 2
1993-07-15 1997-02-25 20.0 3.23: 3 1993-05-17 2002-01-01 20.0 20.0SECOND
QUESTION: I would want to remove rows where t.dif=value in the final result.
Then, I tried: DTNEW <- DT[ , { if (all(start <= opening)){ result <-
list(start, end, t.dif= unclass(round(difftime(end, start)/365.25,1)), value)
} else { result <- list(start, end, t.dif= 20, value) }
result[!(t.dif == value)]}, by=ID] But R does not find the variable t.dif !!
Thank you for your time to all of the members of the list!!
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