[R] automatic completion of object names

knallgrau at gmx.com knallgrau at gmx.com
Fri Jul 6 17:59:15 CEST 2012


Whoops! Thanks to everyone and sorry for asking something so trivial and obvious for everyone. I really hadn't noticed it before.

Cheers!

i.

> > ----- Original Message -----
> > From: David Winsemius
> > Sent: 07/06/12 05:32 PM
> > To: knallgrau at gmx.com
> > Subject: Re: [R] automatic completion of object names
> > 
> > On Jul 6, 2012, at 9:36 AM, knallgrau at gmx.com wrote:
> > 
> > > Hello there,
> > >
> > > I just upgraded to R 2.15 (from R 2.12) on a Windows XP machine and 
> > > noticed some puzzling behaviour (that in my opinion did not exist in 
> > > R 2.12).
> > >
> > > It is possible now to call objects without spelling out the full 
> > > object name. R now seems to use that (unique) object which shares 
> > > the same beginning of the called object, even though the originally 
> > > called object might not even exist.
> > >
> > > This is quite awkwardly described, but perhaps you know what I'm 
> > > talking about?
> > >
> > > Let's say I'm using the Mroz data supplied with the car package:
> > >
> > > require(car)
> > > data(Mroz)
> > >
> > > there is no variable called "w" in that dataframe, but calling
> > >
> > > summary(Mroz$w) #### Mroz$w does not exist
> > >
> > > does not return any error but instead gives the same result as
> > >
> > > summary(Mroz$wc) ##### exists in Mroz
> > >
> > >
> > > I find this behaviour *very* undesirable. Is there any way to switch 
> > > it off?
> > 
> > It has always been the case. See the ?Extract page. The controlling 
> > sentence is here>
> > 
> > " x$name is equivalent to x[["name", exact = FALSE]]. Also, the 
> > partial matching behavior of[[ can be controlled using the exact 
> > argument."
> > 
> > (I'm using R2.14.2 ... further evidence this is not new in 2.15.x)
> > 
> >  > summary(Mroz$w)
> >  no yes
> > 541 212
> > 
> > -- 
> > David Winsemius, MD
> > West Hartford, CT



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