[datatable-help] keyby doesn't sort numeric keys

[Chris Neff]

Hey all,

Using the latest version, I get the following:


> dt=data.table(x=1:10,y=rnorm(10))

> dt[,list(count=.N),keyby=c("x","y")]
Finding groups (bysameorder=FALSE) ... done in 0.003 secs
Detected that j uses these columns (the rest, if any, are ignored for
efficiency):
Starting dogroups ...
testj evaluates to a list with names, this may slow down grouping...
done dogroups in 0.002 secs
       x           y count
 [1,]  1 -0.43990011     1
 [2,]  2 -0.74863035     1
 [3,]  3  0.06791443     1
 [4,]  4  0.32678061     1
 [5,]  5 -0.77222679     1
 [6,]  6  0.03435628     1
 [7,]  7  0.35011434     1
 [8,]  8 -0.46384714     1
 [9,]  9  0.32989082     1
[10,] 10 -0.76977285     1


Note that the y values aren't sorted right.  This output does have x
and y as keys though, and the data.table is left in a state with keys
that aren't sorted.  Unless I misunderstand keyby, this is a bug no?

-Chris