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Where are usages like "== 2L" documented?

7 messages · Steven McKinney, Gabor Grothendieck, Bryan Hanson +1 more

Steven McKinney
# 
?NumericConstants

will bring up a help page that mentions 

"All other numeric constants start with a digit or period and are either a decimal or hexadecimal constant optionally followed by L."

and

"An numeric constant immediately followed by L is regarded as an integer number when possible (and with a warning if it contains a "."). "

but I haven't found discussion of it anywhere else in the help pages.
Others may know what other help pages discuss this.

I'm surprised that the help page invoked from
?integer
does not discuss this.  Anyone know why not?

Best
Steve McKinney
Duncan Murdoch
#
On 16/11/2009 6:47 PM, Steven McKinney wrote:
This is part of the syntax of the language.  It has nothing to do with 
the integer() function, which is what ?integer is asking about.

Duncan Murdoch
Gabor Grothendieck
#
On Mon, Nov 16, 2009 at 7:25 PM, Duncan Murdoch <murdoch at stats.uwo.ca> wrote:
It might be useful to have a SeeAlso to NumericConstants on that help
page for those who looked up ?integer thinking it might be about
integer constants.
Bryan Hanson
# 
As the OP, I will say that I had deduced that it probably was a way of
specifying type integer, so I went to the ?integer page hoping for further
info.  I agree there should be some kind of short comment or see also at
that page.  I've been a self-taught user of R for about a year and a half,
and this is one of the better hidden pieces of information.  I had looked at
the R Lang document, and probably should again for some additional ideas,
but that was a long time ago.  I did an RSiteSearch("1L") but not
surprisingly this returns many uses of the feature, not the definition, at
least not in the first few pages.

Thanks for the tips.  Bryan
*************
Bryan Hanson
Acting Chair
Professor of Chemistry & Biochemistry
DePauw University, Greencastle IN USA
On 11/16/09 7:52 PM, "Gabor Grothendieck" <ggrothendieck at gmail.com> wrote:

            

      
      
      
    

        

      
      
    

  
  


  


      

    

    

      
      

        


  

        

      Steven McKinney
    

    

      
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The word "integer" in the above sentence of the NumericConstants help
page is hyperlinked to the integer() function page.  There is then no
example or discussion of L there.

            

      
      
      
    

        
Yes, additional discussion of "L" would be very valuable.  I've had
several people ask me about usages, as this original poster did.
I think that increased use of L has outpaced updating of help entries.
Given that L is appearing in more places, I'd like to request additional
discussion of it and examples using it in help pages.

            

      
      
      
    

        
[1] "integer"

            

      
      
      
    

        
[1] "integer"

Since "integer" is the term often associated with this language construct,
that seems a natural place to say something about it, and direct users
to other appropriate help pages.

The help page for storage.mode() shows an example with "1i" in it,
could "1L" please also be added?  ("1.0" or "1." would also be useful.)

cex3 <- c("NULL","1","1:1","1i","list(1)","data.frame(x=1)",
  "pairlist(pi)", "c", "lm", "formals(lm)[[1]]",  "formals(lm)[[2]]",
  "y~x","expression((1))[[1]]", "(y~x)[[1]]",
  "expression(x <- pi)[[1]][[1]]")


The "L" language construct is often used in length checks such as
in the sample() function " if (length(x) == 1L ..."

The length() function help page discusses
" The default method currently returns an integer of length 1."
again with the "integer" hyperlinked to the integer() help page.
Since length() therefore can only assess integer lengths
from 0 to about 2^31 - 1 it would be helpful to discuss this
integer "L" construct and the range of values that can be expressed
with mode "integer" more fully somewhere in one of these help topics.

            

      
      
      
    

        
function (x, size, replace = FALSE, prob = NULL) 
{
    if (length(x) == 1L && is.numeric(x) && x >= 1) {
        if (missing(size)) 
            size <- x
        .Internal(sample(x, size, replace, prob))
    }
    else {
        if (missing(size)) 
            size <- length(x)
        x[.Internal(sample(length(x), size, replace, prob))]
    }
}
<environment: namespace:base>


Best
Steve McKinney

  
  


  


      

    

    

      
      

        


  

        

      Duncan Murdoch
    

    

      
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I think your suggestions below indicate a difference in documentation 
philosophy between us.  I believe that things should be documented well 
in one place, and it should be easy to find that one place; you seem to 
be suggesting spreading out bits and pieces of documentation to many places.

The disadvantage of the many-place style is that it is hard to look up 
details.  I may remember seeing somewhere various rules about something, 
but if it isn't clear where to look for it again, I will have trouble 
finding it.

The weakness of the one-place style is that it isn't always easy to find 
that one place.  R documentation especially suffers from this, because 
it is hard to find things in the manuals if you're looking in the help() 
system.  I think the solution is to make it easier to find things in the 
manuals, rather than repeating bits and pieces of the manuals all across 
the help system.

One way to do this is to link the manuals into the help system, and I 
did some work on this last year, but unfortunately this requires a newer 
version of Texinfo than we are allowed to use because of FSF license 
restrictions.

Duncan Murdoch

        
On 16/11/2009 9:09 PM, Steven McKinney wrote:

            

      
      
      
    

        

      
      
    

  
  


  


      

    

    

      
      

        


  

        

      Duncan Murdoch
    

    

      
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On 16/11/2009 7:52 PM, Gabor Grothendieck wrote:

            

      
      
      
    

        
I've added "1L", "1i" and "0x1" as aliases for NumericConstants instead.

Duncan Murdoch