R community, I would like to know how to extract rows from a data frame (DF) such that each row in the new data frame (D.F) represents the first instance of a unique variable pairing in the original dataframe (ordered first by variable V1 then by variable V2). The unique function does not seem to be able to accomplish this. I imagine there must be a simple solution for this, but I can't seem to find it. Thank you, Mike DF <- structure(list(V1 = c(1, 1, 1, 1, 2, 2, 2, 2), V2 = c(1, 1, 2, 2, 1, 1, 2, 2), V3 = c(1L, 8L, 4L, 3L, 6L, 2L, 7L, 5L), V4 = c(8L, 3L, 6L, 1L, 2L, 4L, 5L, 7L)), .Names = c("V1", "V2", "V3", "V4"), row.names = c(NA, -8L), class = "data.frame")
D.F <- structure(list(V.1 = c(1, 1, 2, 2), V.2 = c(1, 2, 1, 2), V.3 = c(1, 4, 6, 7), V.4 = c(8, 6, 2, 5)), .Names = c("V.1", "V.2", "V.3", "V.4"), row.names = c(NA, -4L), class = "data.frame") _________________________________________________________________ Hotmail is redefining busy with tools for the New Busy. Get more from your inbox. N:WL:en-US:WM_HMP:042010_2 ______________________________________________ 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.