of course it is. virtually everything in R is somewhere documented, and once one sees it, pretty well documented, too.
my suggestion for a warning is more a matter of "user friendliness"---a warning, not an error. chances are that if a variable exists in the upper frames, and a user reuses it, there is a good chance that it could be ambiguous. for such cases, a user may be well advised to use subset$variablename explicitly instead of simply variablename IMHO. I believe many C compilers and the perl interpreter routinely issue warnings when there is a good chance that a behavior may not necessarily be what a naive user might expect, even though the code is perfectly correct and unambiguous. of course, I am really NAIVE very often. regards, /ivo On 5/17/07, Bert Gunter <[EMAIL PROTECTED]> wrote: > ... but it **is** explicitly documented in ?subset: > > "For data frames, the subset argument works on the rows. Note that subset > will be evaluated in the data frame, so columns can be referred to (by name) > as variables in the expression (see the examples). " > > > Bert Gunter > Genentech Nonclinical Statistics > > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of ivo welch > Sent: Thursday, May 17, 2007 11:53 AM > To: jim holtman > Cc: r-help > Subject: Re: [R] bug or feature? > > ahh...it is the silent substitution of the data frame in the subset > statement. I should have known this. (PS: this may not be desirable > behavior; maybe it would be useful to issue a warning if the same name > is defined in an upper data frame. just an opinion...) > > mea misunderstanding. > > /iaw > > ______________________________________________ > [email protected] 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. > > ______________________________________________ [email protected] 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.
