Hello, I am very new to R and have hit my first main problem that I hope someone can easily resolve.
I have some data that looks like this (there are 20,000 rows): > qdata day month year flow [1,] 2 10 1945 NA [2,] 3 10 1945 NA [3,] 4 10 1945 NA [4,] 5 10 1945 NA [5,] 6 10 1945 2.973 [6,] 7 10 1945 NA [7,] 8 10 1945 NA [8,] 9 10 1945 2.973 [9,] 10 10 1945 NA [10,] 11 10 1945 NA [11,] 12 10 1945 NA [12,] 13 10 1945 NA [13,] 14 10 1945 2.973 [14,] 15 10 1945 NA I want to sort the data in descending order by flow but with all the NA results sent to the bottom. I have managed to sort the data using: topflows <- qdata[order(-flow, na.last=TRUE),] But this sorts the data by flow value and then year I think giving: day month year flow [1,] 14 3 1947 222.40 [2,] 15 3 1947 NA [3,] 18 3 1947 NA [4,] 17 3 1947 NA [5,] 19 3 1947 NA [6,] 12 3 1947 NA [7,] 13 3 1947 NA [8,] 16 3 1947 NA [9,] 20 3 1947 NA [10,] 30 11 1946 106.50 [11,] 30 3 1947 105.60 [12,] 29 11 1946 NA [13,] 11 3 1947 NA [14,] 22 11 1946 99.96 [15,] 21 11 1946 NA I want my data to come out like this: [1,] 14 3 1947 222.3 [2,] 30 11 1946 106.50 [3,] 30 3 1947 105.60 [4,] 22 11 1946 99.96 and so on... Any help would be greatly valued. Thanks Emma -- View this message in context: http://n4.nabble.com/sorting-data-whilst-ignoring-NA-s-tp1586277p1586277.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.