[datatable-help] possible bug when running setkey on POSIXct column

[jim holtman]

seems to work for me:

> library(data.table)
data.table 1.8.6  For help type: help("data.table")
> DT = data.table(X=as.POSIXct( c(rep("15DEC2008:00:00:00",10),"15DEC2008:00:00:00",rep("17DEC2008:00:00:00",2)),format="%d%b%Y:%H:%M:%S"),Y=c(1534,61,74,518,519,1519,1520,1524,3127,29250,30609,43,7853))
> setkey(DT,X,Y)
> DT
             X     Y
 1: 2008-12-15    61
 2: 2008-12-15    74
 3: 2008-12-15   518
 4: 2008-12-15   519
 5: 2008-12-15  1519
 6: 2008-12-15  1520
 7: 2008-12-15  1524
 8: 2008-12-15  1534
 9: 2008-12-15  3127
10: 2008-12-15 29250
11: 2008-12-15 30609
12: 2008-12-17    43
13: 2008-12-17  7853


On Fri, Jan 18, 2013 at 9:44 AM, statquant <statquant at outlook.com> wrote:
> Hello I might have found a bug.
> I really cannot explain the following (please be indulgent as I narrowed the
> most I could).
>
> library(data.table)
> DT = data.table(X=as.POSIXct(
> c(rep("15DEC2008:00:00:00",10),"15DEC2008:00:00:00",rep("17DEC2008:00:00:00",2)),format="%d%b%Y:%H:%M:%S"),Y=c(1534,61,74,518,519,1519,1520,1524,3127,29250,30609,43,7853))
> setkey(DT,X,Y)
>
> #Here is what I see after the sort
>
> DT
>              X     Y
>  1: 2008-12-15  1534
>  2: 2008-12-15    61
>  3: 2008-12-15    74
>  4: 2008-12-15   518
>  5: 2008-12-15   519
>  6: 2008-12-15  1519
>  7: 2008-12-15  1520
>  8: 2008-12-15  1524
>  9: 2008-12-15  3127
> 10: 2008-12-15 29250
> 11: 2008-12-15 30609
> 12: 2008-12-17    43
> 13: 2008-12-17  7853
>
> #I thought that it was a POSIXct problem but if I can get the correct answer
> like this:
>
> DT[order(X,Y),]
>              X     Y
>  1: 2008-12-15    61
>  2: 2008-12-15    62
>  3: 2008-12-15    74
>  4: 2008-12-15   518
>  5: 2008-12-15   519
>  6: 2008-12-15  1519
>  7: 2008-12-15  1520
>  8: 2008-12-15  1524
>  9: 2008-12-15  3127
> 10: 2008-12-15 29250
> 11: 2008-12-15 30609
> 12: 2008-12-17    43
> 13: 2008-12-17  7853
>
> #Here is my session (just launched it)
>
> R> sessionInfo()
> R version 2.15.2 (2012-10-26)
> Platform: x86_64-pc-linux-gnu (64-bit)
>
> locale:
>  [1] LC_CTYPE=en_GB.UTF-8       LC_NUMERIC=C               LC_TIME=C
>  [4] LC_COLLATE=en_GB.UTF-8     LC_MONETARY=fr_FR.UTF-8
> LC_MESSAGES=en_GB.UTF-8
>  [7] LC_PAPER=C                 LC_NAME=C                  LC_ADDRESS=C
> [10] LC_TELEPHONE=C             LC_MEASUREMENT=fr_FR.UTF-8
> LC_IDENTIFICATION=C
>
> attached base packages:
> [1] stats     graphics  grDevices datasets  utils     methods   base
>
> other attached packages:
> [1] data.table_1.8.7 inline_0.3.10    Rcpp_0.10.2      vimcom_0.9-5
> setwidth_1.0-2
> [6] colorout_0.9-9
>
>
>
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> datatable-help at lists.r-forge.r-project.org
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-- 
Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.