Dear all, I have a dataset (below) by ID and time sequence. I would like to sum every four observations by ID.
I am confused how to combine the two conditions. Any help will be highly appreciated. Thank you! Best. Milu ## Dataset structure(list(ID = c("A", "A", "A", "A", "A", "A", "A", "A", "B", "B", "B", "B", "B", "B", "B", "B", "C", "C", "C", "C", "C", "C", "C", "C"), Date = c(4140L, 4141L, 4142L, 4143L, 4144L, 4145L, 4146L, 4147L, 4140L, 4141L, 4142L, 4143L, 4144L, 4145L, 4146L, 4147L, 4140L, 4141L, 4142L, 4143L, 4144L, 4145L, 4146L, 4147L ), Value = c(0.000207232, 0.000240141, 0.000271414, 0.000258384, 0.00024364, 0.00027148, 0.000280585, 0.000289691, 0.000298797, 0.000307903, 0.000317008, 0.000326114, 0.00033522, 0.000344326, 0.000353431, 0.000362537, 0.000371643, 0.000380749, 0.000389854, 0.00039896, 0.000408066, 0.000417172, 0.000426277, 0.000435383 )), class = "data.frame", row.names = c(NA, -24L)) [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.