Sort rows in data.table in decreasing order on string key `order(-x,v)` gives error on data.table 1.9.4 or earlier

Question

Let\'s say I have the following data.table in R:

  library(data.table)
  DT = data.table(x=rep(c(\"b\",\"a\",\"c\"),each=3), y=c(1,3,6)         


        

Answer 1

Update

data.table v1.9.6+ now supports OP's original attempt and the following answer is no longer necessary.

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You can use DT[order(-rank(x), y)].

   x y v
1: c 1 7
2: c 3 8
3: c 6 9
4: b 1 1
5: b 3 2
6: b 6 3
7: a 1 4
8: a 3 5
9: a 6 6