You can use the order() function directly without resorting to add-on tools -- see this simpler answer which uses a trick right from the top of the example(order) code:
R> dd[with(dd, order(-z, b)), ] b x y z 4 Low C 9 2 2 Med D 3 1 1 Hi A 8 1 3 Hi A 9 1 Edit some 2+ years later: It was just asked how to do this by column index. The answer is to simply pass the desired sorting column(s) to the order() function:
R> dd[order(-dd[,4], dd[,1]), ] b x y z 4 Low C 9 2 2 Med D 3 1 1 Hi A 8 1 3 Hi A 9 1 R> rather than using the name of the column (and with() for easier/more direct access).
If you use minus with a character column, you get an error:
dd$x <- as.character(dd$x) dd[order(-dd[,2], dd[,1]), ] ## Error in -dd[, 2] : invalid argument to unary operator In this case you need to wrap the argument in xtfrm.
dd[order(-xtfrm(dd[,2]), dd[,1]), ] 