Gregor Gorjanc wrote: > Gregor Gorjanc wrote: >> Hello useRs! >> >> I have a small package and I need internet access for examples. Of >> course it works fine when I have internet access, but not otherwise. I >> remember I saw a way to test availability of internet access, but I can >> not find it now in archives. Can anyone here help me? >> >> David Barron wrote: >>> I means non-zero, not non-negative. >>> >> ... >> >> Thanks. download.file() is fine! >> > > Thinking a bit more, download.file() is not really general as I need to > specify an url and it might happen that I have internet connection, but > server that provides url is down. I am to picky on this?
Additionally, download.file throws an error if url is not available i.e. if I do not have internet access. I have used the following example: if(download.file(url="http://www.r-project.org/index.html";, destfile=tempfile()) == 0) { print("Yuhuu") } unpluged the net cable and got the following message during R CMD check (in examples part) trying URL 'http://www.r-project.org/index.html' Warning: unable to resolve 'www.r-project.org'. Error in download.file(url = "http://www.r-project.org/index.html";, destfile = tempfile()) : cannot open URL 'http://www.r-project.org/index.html' Execution halted It seems that 'internal' method was used (I use R 2.3.1 under Linux) as indicated in help page of download.file. I could use wget or lynx methods, but these two must be available, so this is not really portable. Are there any other options for testing internet access? I am thinking that this might be more relevant for R-devel. I will wait a bit before moving there. -- Lep pozdrav / With regards, Gregor Gorjanc ---------------------------------------------------------------------- University of Ljubljana PhD student Biotechnical Faculty Zootechnical Department URI: http://www.bfro.uni-lj.si/MR/ggorjan Groblje 3 mail: gregor.gorjanc <at> bfro.uni-lj.si SI-1230 Domzale tel: +386 (0)1 72 17 861 Slovenia, Europe fax: +386 (0)1 72 17 888 ---------------------------------------------------------------------- "One must learn by doing the thing; for though you think you know it, you have no certainty until you try." Sophocles ~ 450 B.C. ______________________________________________ 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 and provide commented, minimal, self-contained, reproducible code.
