[R] Non-visible functions are asterisked

[Duncan Murdoch]

On 08/03/2008 10:48 AM, Muenchen, Robert A (Bob) wrote:
> Dear R-Helpers,
> 
> I suspect I'm about to ask a FAQ, but I haven't been able to find an
> answer in the FAQ, AItR or an R Site Search. When I look at the methods
> of summary (below) it says, "Non-visible functions are asterisked". I
> looked at the help file for summary.princomp, which did not comment on
> it being non-visible. I ran its help file example, which printed visible
> output. I did not notice how it differed from other functions, like
> summary.data.frame that is not marked non-invisible. What does the
> non-visible mean?
> 
> Thanks,
> Bob 
> 
>> methods(summary)
>  [1] summary.aov            summary.aovlist       
>  [3] summary.connection     summary.data.frame    
>  [5] summary.Date           summary.default       
>  [7] summary.ecdf*          summary.factor        
>  [9] summary.glm            summary.infl          
> [11] summary.lm             summary.loess*        
> [13] summary.manova         summary.matrix        
> [15] summary.mlm            summary.nls*          
> [17] summary.packageStatus* summary.POSIXct       
> [19] summary.POSIXlt        summary.ppr*          
> [21] summary.prcomp*        summary.princomp*     
> [23] summary.stepfun        summary.stl*          
> [25] summary.table          summary.tukeysmooth*  
> 
>    Non-visible functions are asterisked

Try this:
 > summary.princomp
Error: object "summary.princomp" not found
 > summary.data.frame
function (object, maxsum = 7, digits = max(3, getOption("digits") -
     3), ...)
{

  etc.

R can find summary.princomp when it runs UseMethod, but it's hidden in 
the stats namespace, so you need to use "stats:::summary.princomp" to 
see it.

Duncan Murdoch