R is lazy, but not quite that lazy ;-) It's likely much easier to do this with regexps
something like list.files()[grepl(paste0(filename, "-"[0123456789]+""), list.files())] Michael On Mon, May 14, 2012 at 3:34 PM, J Toll <jct...@gmail.com> wrote: > Hi, > > I have a question involving Inf, lazy evaluation, and maybe argument > recycling. I have a directory where I am trying to check for the > existence of files of a certain pattern, basically something like > "filename-#", where # is an integer. I can do something like this, > which works. > > file.exists(paste(filename, "-", 1:100, sep = "")) > > But I don't like the fact that I am only checking the first 100 > possibilities. What I would prefer is this: > > file.exists(paste(filename, "-", 1:Inf, sep = "")) > > But that doesn't work, I get the error: > > Error in 1:Inf : result would be too long a vector > > On one hand, with lazy evaluation, you would think that 1:Inf should > work. On the other hand, I'm not quite sure what the output would be > if it was working, especially if there were large gaps in the > integers. Is there a way to get the behavior I seek (i.e. the lazy > evaluation of 1:Inf). > > Thanks, > > > James > > ______________________________________________ > 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. ______________________________________________ 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.
