See pages 45 and 46 of V&R's S PROGRAMMING for a definitive discussion of how to do this.
(Confession: I treat anything that V&R say as definitive). Cheers, Bert Gunter > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Gabor > Grothendieck > Sent: Thursday, June 30, 2005 4:34 AM > To: Oleg Sklyar > Cc: r-help@stat.math.ethz.ch > Subject: Re: [R] parsing '...' function argument? > > On 6/30/05, Oleg Sklyar <[EMAIL PROTECTED]> wrote: > > Dear community, > > > > I am writing a wrapper for '[' operator, which is a generic method > > declared as function(x, i, j, ..., drop). It turns out that > I need to > > parse the '...' argument and this is where I am stuck. > Generally what I > > need is the following. Say the call is obj[1, 1, 1:10, 3] - > here '1:10, > > 3' is passed into '...'. What I need to evaluate that '...' > contains now > > 2 arguments, first is a vector of 10 elements and second is a single > > value. Even nicer situation is in call obj[1, 1, , 3] - > where ' , 3' is > > passed in '...' with one missing argument, which for an > array would mean > > the full range. Any ideas? (Just to mention - if there were only one > > argument in '...', say '1:10', then length(...) would > return 10 and one > > could access elements by ...[[i]], but all this fails if > there are two > > arguments or more). > > > > Check out the technique used in this post: > > http://tolstoy.newcastle.edu.au/R/help/04/06/1430.html > > ______________________________________________ > R-help@stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html > ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html