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

[Chris Neff]

Ignore me I am being stupid!




On Tue, May 15, 2012 at 12:04 PM, Chris Neff <caneff at gmail.com> wrote:
> 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