Dear R members, I have this data frame of 100 years in the following format
year month day A B C D where A,B,C and D are item number sold each day. I am trying 1-split the data w.r.t the monthly values for each year 2-then, sum them up I am pasting here just a part of data to make it more clearer structure(list(year = c(1961, 1961, 1961, 1961, 1961, 1961, 1961, 1961, 1961, 1961, 1961, 1961), month = c(1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1), day = 1:12, A = 1:12, B = 3:14, C = 6:17, D = 16:27), .Names = c("year", "month", "day", "A", "B", "C", "D"), row.names = c(NA, 12L), class = "data.frame") I initially tried to use "dcast" command but for no use. Your kind help is needed. Thanks in advance Eliza [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list 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.