Check to see if a value is within a range?

Question

I have a dataset in a data.table format that looks as such:

ID     time.s     time.e
1       1         2
2       1         4
3       2         3         


        

Answer 1

Assuming that the values of ID are unique:

DT[, list(OK = 1 %in% seq(time.s, time.e)), by = ID]

giving;

   ID    OK
1:  1  TRUE
2:  2  TRUE
3:  3 FALSE
4:  4 FALSE