On Sun, Aug 9, 2009 at 11:32 AM, Ted Harding<ted.hard...@manchester.ac.uk> wrote: > On 09-Aug-09 16:06:52, Peng Yu wrote: >> Hi, >> I know '.' is not a separator in R as in C++. I am wondering where it >> discusses the detailed usage of '.' in R. Can somebody point me a >> webpage, a manual or a book that discuss this? >> >> Regards, >> Peng > > To the best of my knowledge, apart from its specific use as a separator > between the integer and fractional parts of a number, "." has no specific > use in R, and you can, for instance, use it just as you would use an > alphanumeric character in a name. > > For instance, you could do > > . <- 1.2345 > . > # [1] 1.2345 > > . <- function(x) x^2 > .(12) > # [1] 144 > > So, unless there is something I don't know about, there is hardly > anything to discuss about "the detailed usage of '.' in R"!
The ',' character is one of the characters allowed in names, hence it can be used as you have suggested. There are (at least) two special usages of the '.' in names. Following the time-honoured Unix convention, names that begin with '.' are considered "hidden" names and not listed by ls() or objects() unless you set all.names = TRUE in the call. Because of this convention it is inadvisable to use names starting with '.' except when you wish to avoid potential name conflicts. The second special use of '.' in a name is in the construction of the names of S3 method functions. The method for generic function "foo" applied to class "bar" is named "foo.bar". ______________________________________________ R-help@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.
