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stringsAsFactors param in expand.grid not working

3 messages · Steve Lianoglou, Rolf Turner, Martin Maechler

Steve Lianoglou
# 
Hi all,

I've (tried) to look through the bug tracker, and gmane-search the R list to 
see if this has been mentioned before, and it looks like it hasn't.

According to the R 2.9.0 release notes[1], the expand.grid function should now 
take a stringsAsFactor=LOGICAL argument which controls whether or not the 
function coerces strings as factors. While the parameter is indeed in the 
function, a quick examination of the function's source shows that the value 
of this argument is never checked, and all strings are converted to factors 
as a matter of course.

The fix is pretty easy, and I believe only requires changing the `if` check 
here:

if (!is.factor(x) && is.character(x)) 
    x <- factor(x, levels = unique(x))

To:

if (!is.factor(x) && is.character(x) && stringsAsFactors) 
    x <- factor(x, levels = unique(x))

I can open a ticket regarding this issue and add this there if necessary.

Thanks,
-steve

[1] http://article.gmane.org/gmane.comp.lang.r.general/146891
Rolf Turner
#
On 19/05/2009, at 10:20 AM, Steve Lianoglou wrote:

            

      
      
      
    

        
While we're at it --- would it not make sense to have the  
stringsAsFactors
argument (once it's working) of expand.grid() default to options() 
$stringsAsFactors,
rather than to FALSE?

This would make no difference to me personally, since I set
options(stringsAsFactors=FALSE) in my .Rprofile.  But it might make some
people happier ....

	cheers,

		Rolf Turner

######################################################################
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      Martin Maechler
    

    

      
      #
    

  


  

          

      
      
      
    

        

        
RT> On 19/05/2009, at 10:20 AM, Steve Lianoglou wrote:

        
>> Hi all,
    >> 
    >> I've (tried) to look through the bug tracker, and gmane-search the  
    >> R list to
    >> see if this has been mentioned before, and it looks like it hasn't.

Yes, thank you.

That's a bug on which we  (R-core) currently work.
More about this, and notably about Rolf's (.)*&^%)(&#%$)
proposal on the   R-devel  list.

Martin Maechler


    >> According to the R 2.9.0 release notes[1], the expand.grid function  
    >> should now
    >> take a stringsAsFactor=LOGICAL argument which controls whether or  
    >> not the
    >> function coerces strings as factors. While the parameter is indeed  
    >> in the
    >> function, a quick examination of the function's source shows that  
    >> the value
    >> of this argument is never checked, and all strings are converted to  
    >> factors
    >> as a matter of course.
    >> 
    >> The fix is pretty easy, and I believe only requires changing the  
    >> `if` check
    >> here:
    >> 
    >> if (!is.factor(x) && is.character(x))
    >> x <- factor(x, levels = unique(x))
    >> 
    >> To:
    >> 
    >> if (!is.factor(x) && is.character(x) && stringsAsFactors)
    >> x <- factor(x, levels = unique(x))
    >> 
    >> I can open a ticket regarding this issue and add this there if  
    >> necessary.
    >> 
    >> Thanks,
    >> -steve
    >> 
    >> [1] http://article.gmane.org/gmane.comp.lang.r.general/146891

    RT> While we're at it --- would it not make sense to have the  
    RT> stringsAsFactors
    RT> argument (once it's working) of expand.grid() default to options() 
    RT> $stringsAsFactors,
    RT> rather than to FALSE?

    RT> This would make no difference to me personally, since I set
    RT> options(stringsAsFactors=FALSE) in my .Rprofile.  But it might make some
    RT> people happier ....

    RT> cheers,

    RT> Rolf Turner

    RT> ######################################################################
    RT> Attention:\ This e-mail message is privileged and confid...{{dropped:9}}

    RT> ______________________________________________
    RT> R-help at r-project.org mailing list
    RT> https://stat.ethz.ch/mailman/listinfo/r-help
    RT> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
    RT> and provide commented, minimal, self-contained, reproducible code.