See ?try ?tryCatch
On Mon, 18 Sep 2006, Stefan Th. Gries wrote: > Hi > > I wrote a script which retrieves links from websites and loads them with scan: > > ... > website<-tolower(scan(current.pages[i], what="character", sep="\n", > quiet=TRUE)) > ... > > However occasionally, the script finds broken links, such as > <http://www.google.com/test>. when the script tries to access such websites, > the repeat loop breaks and I get the error message > > Error in file(file, "r") : unable to open connection > In addition: Warning message: > cannot open: HTTP status was '404 Not Found' > > Now my question: is there a way to test whether the target of a link exists > that does not result in an error and, thus, discontinues my loop? I looked at > the help files for files, scans, connections, and did a search for "404?' in > th archives but couldn't find anything. I work with R 2.3.1 patched on > Windows XP (both Home and Prof) and would appreciate any pointers ... > Thanks a lot, > STG -- Brian D. Ripley, [EMAIL PROTECTED] Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595 ______________________________________________ [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.
