Where are usages like "== 2L" documented?
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:
-----Original Message----- From: Gabor Grothendieck [mailto:ggrothendieck at gmail.com] Sent: Monday, November 16, 2009 4:52 PM To: Duncan Murdoch Cc: Steven McKinney; R Help Subject: Re: [R] Where are usages like "== 2L" documented? On Mon, Nov 16, 2009 at 7:25 PM, Duncan Murdoch <murdoch at stats.uwo.ca> wrote:
On 16/11/2009 6:47 PM, Steven McKinney wrote:
?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 "."). "
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.
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?
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.
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.
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.
class(1L)
[1] "integer"
storage.mode(1L)
[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.
sample
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
______________________________________________ R-help at r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.