[datatable-help] Unexpected behavior in setnames()

[Arunkumar Srinivasan]

Sorry, forget the j-value. For `.SDcols`, even when we provide integers (column numbers), internally, we compute the column name and subset to get `.SD`. And this'll have to change. 

Arun


On Friday, November 8, 2013 at 9:47 PM, Steve Lianoglou wrote:

> On Fri, Nov 8, 2013 at 12:45 PM, Arunkumar Srinivasan
> <aragorn168b at gmail.com (mailto:aragorn168b at gmail.com)> wrote:
> > Oh I can certainly agree with that. I guess we'll have to make some changes
> > to the code to use index based subsetting when .SDcols or j-value is number
> > then.
> > 
> 
> 
> Not sure what you mean by j-value -- the examples you gave didn't
> compute on the .SD, it just returned it.
> 
> I think if there is a `j` expression that computes on an .SD that has
> duplicated colnames, I think we just stop().
> 
> Or did you mean something else?
> 
> -steve
> 
> > On Friday, November 8, 2013 at 9:41 PM, Steve Lianoglou wrote:
> > 
> > My gut reaction is:
> > 
> > On Fri, Nov 8, 2013 at 12:37 PM, Arunkumar Srinivasan
> > <aragorn168b at gmail.com (mailto:aragorn168b at gmail.com)> wrote:
> > 
> > Sure, here's an example of what I was trying to explain:
> > 
> > Suppose:
> > DT <- data.table(x=1:5, y=1:5, x=6:10)
> > 
> > Then,
> > 
> > DT[, c(1,3), with=FALSE] # gives correct subset
> > 
> > 
> > This is "OK", we just do what the user asks, here, as they are being
> > very specific.
> > 
> > DT[, c("x", "x"), with=FALSE] # gives column 1 twice - wrong
> > 
> > 
> > stop() -- we don't try to disambiguate (even if it "seems" specific)
> > 
> > DT[, .SD, .SDcols=c("x", "x")] # gives column 1 twice - wrong result
> > 
> > 
> > stop()
> > 
> > Also stop() on DT[, ..., .SDcols="x"]
> > 
> > DT[, .SD, .SDcols=c(1,3)] # gives column 1 twice - wrong result - but
> > 
> > 
> > Do what the user asks for.
> > 
> > No?
> > 
> > -steve
> > 
> > --
> > Steve Lianoglou
> > Computational Biologist
> > Bioinformatics and Computational Biology
> > Genentech
> > 
> > 
> > 
> > _______________________________________________
> > datatable-help mailing list
> > datatable-help at lists.r-forge.r-project.org (mailto:datatable-help at lists.r-forge.r-project.org)
> > https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help
> > 
> 
> 
> 
> 
> -- 
> Steve Lianoglou
> Computational Biologist
> Bioinformatics and Computational Biology
> Genentech
> 
> 


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.r-forge.r-project.org/pipermail/datatable-help/attachments/20131108/2527028d/attachment.html>