Dear all, I have weekly data by city (variable citycode). I would like to take the average of the previous two, three, four weeks (without the current week) of the variable called value.
This is what I have tried to compute the average of the two previous weeks; df = df %>% mutate(value.lag1 = lag(value, n = 1)) %>% mutate(value .2.previous = rollapply(data = value.lag1, width = 2, FUN = mean, align = "right", fill = NA, na.rm = T)) I crated the lag of the variable first and then attempted to compute the average but this does not seem to to what I want. What I am doing wrong? Any help will be appreciated. The data is below. Thank you. Sincerely, Milu dput(droplevels(head(df, 10))) structure(list(year = c(1970L, 1970L, 1970L, 1970L, 1970L, 1970L, 1970L, 1970L, 1970L, 1970L), citycode = c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L), month = c(1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 3L), week = c(1L, 2L, 3L, 4L, 5L, 5L, 6L, 7L, 8L, 9L), date = structure(c(1L, 2L, 3L, 4L, 5L, 5L, 6L, 7L, 8L, 9L), .Label = c("1970-01-10", "1970-01-17", "1970-01-24", "1970-01-31", "1970-02-07", "1970-02-14", "1970-02-21", "1970-02-28", "1970-03-07"), class = "factor"), value = c(-15.035, -20.478, -22.245, -23.576, -8.84099999999995, -18.497, -13.892, -18.974, -15.919, -13.576)), .Names = c("year", "citycode", "month", "week", "date", "tmin"), row.names = c(NA, 10L), class = "data.frame") [[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.