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

Matthew Dowle Sun, 20 Jan 2013 08:14:00 -0800


Indeed. I reproduced. Now fixed. Well done and thanks statquant.

o setkey could sort 'double' columns (such as POSIXct) incorrectly whennot the

  last column of the key, #2484. In data.table's C code :
     x[a]>x[b]-tol
  should have been :
     x[a]-x[b]>-tol  [or  x[b]-x[a]<tol ]

The difference may have been machine/compiler dependent. Many thanksto statquant

  for the short reproducible example. Test added.


On 18.01.2013 21:48, Erik Iverson wrote:

Jim, what platform are you on? I can reproduce on Linux (and indeed
recently saw something similar with my own data).

Best,
--Erik

On Fri, Jan 18, 2013 at 3:45 PM, jim holtman <[email protected]>wrote:


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 <[email protected]>wrote:

> Hello I might have found a bug.

> I really cannot explain the following (please be indulgent as Inarrowed

> 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 thecorrect

> 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=CLC_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=CLC_ADDRESS=C

> [10] LC_TELEPHONE=C             LC_MEASUREMENT=fr_FR.UTF-8
> LC_IDENTIFICATION=C
>
> attached base packages:

> [1] stats graphics grDevices datasets utils methodsbase

>
> other attached packages:

> [1] data.table_1.8.7 inline_0.3.10 Rcpp_0.10.2vimcom_0.9-5

> setwidth_1.0-2
> [6] colorout_0.9-9
>
>
>
> _______________________________________________
> datatable-help mailing list
> [email protected]
>

>https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help




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

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