[datatable-help] Can crash R with a data.table query

[Short, Tom]

That crashes R for me, too, somewhere in data.table.dll.

- Tom


 

> -----Original Message-----
> From: datatable-help-bounces at lists.r-forge.r-project.org 
> [mailto:datatable-help-bounces at lists.r-forge.r-project.org] 
> On Behalf Of mdowle at mdowle.plus.com
> Sent: Thursday, July 01, 2010 05:33
> To: Harish
> Cc: datatable-help at lists.r-forge.r-project.org
> Subject: Re: [datatable-help] Can crash R with a data.table query
> 
> What you mean by 'crash'? R simply stops or theres a message?
> Try the clean install of latest 1.5, as per recent reply on 
> other thread, and can go from there...
> 
> > Hi,
> >
> > I am crashing R with the following code (and it might have 
> something 
> > to do with data tables as well):
> >
> > =========
> >
> >
> > DT <- structure(list(A = c(25L, 85L, 25L, 25L, 85L), B = 
> > structure(c(1L, 1L, 2L, 3L, 3L), .Label = c("a", "b", "c"), 
> class = "factor"),
> >     C = c(2L, 65L, 9L, 82L, 823L)), .Names = c("A", "B", 
> "C"), class = 
> > c("data.table", "data.frame"), row.names = c(NA, -5L))
> >
> > DT[ , data.table( A, C )[ A==25, C ] + data.table( A, C )[ 
> A==85, C ], 
> > by=B ]
> >
> > =========
> >
> > For every B, I am trying to sum the C's where A is 25 and 85.
> >
> > The crash has something to do with my row selection 
> criteria.  First, 
> > note that for B=="b", I don't have A==85.  It looks like a 
> numeric(0) 
> > is being returned in this case.
> >
> > In order to avoid the crash, I had to do something like:
> >    if ( ! identical( DT[ blah ], numeric( 0 ) )
> >
> > It isn't just that R is unable to handle operations on numeric(0) 
> > because I don't get a crash when I just type in "numeric(0) 
> + 2".  So, 
> > my guess is that it has something to do with data.table as well.
> >
> >
> > Harish
> >
> >
> >
> >
> > _______________________________________________
> > datatable-help mailing list
> > datatable-help at lists.r-forge.r-project.org
> > 
> https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable
> > -help
> >
> 
> 
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