You can use file.info("myFile") to make sure the file exists and has appropriate permissions ("mode" in file.info's lingo, as in Unix). E.g.,
> file.info("c:/temp/BO.jpeg") # this one does not exist size isdir mode mtime ctime atime exe c:/temp/BO.jpeg NA NA <NA> <NA> <NA> <NA> <NA> > file.info("c:/temp/BO.jpg") # this one exists size isdir mode mtime ctime atime c:/temp/BO.jpg 150536 FALSE 666 2013-01-14 08:35:32 2013-01-14 08:33:09 2013-01-14 08:33:09 exe c:/temp/BO.jpg no I can readJPEG() the file with mode 666, but not all permission information is encoded in the mode. Bill Dunlap Spotfire, TIBCO Software wdunlap tibco.com > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On > Behalf > Of Jeff Newmiller > Sent: Monday, January 14, 2013 8:25 AM > To: Yi Yuan; r-help@r-project.org > Subject: Re: [R] readJPEG function cannot open jpeg files > > Being unable to open a file is a related to your operating system and how R > interacts with > that OS. If your interactive development environment (IDE, of which RStudio > is an > example) is trying to make things simpler for you but you don't understand > how to use it, > then you need to ask help from your RStudio support resources, not here. > > When posting here, you should mention your results from using base R > functions like > > ?sessionInfo > ?getwd > ?list.files > > as indicated in the Posting Guide mentioned at the bottom of every R-help > email. > > Consistent with the fact that this is an interface issue between R and the > OS, sometimes > you will have to investigate the problem from outside R. For example, you > might need to > investigate issues with security permissions that are OS specific and > completely outside > the scope of this forum. > --------------------------------------------------------------------------- > Jeff Newmiller The ..... ..... Go Live... > DCN:<jdnew...@dcn.davis.ca.us> Basics: ##.#. ##.#. Live Go... > Live: OO#.. Dead: OO#.. Playing > Research Engineer (Solar/Batteries O.O#. #.O#. with > /Software/Embedded Controllers) .OO#. .OO#. rocks...1k > --------------------------------------------------------------------------- > Sent from my phone. Please excuse my brevity. > > Yi Yuan <lamban...@gmail.com> wrote: > > >I installed jpeg package and tried to use > > > >kim<-readJPEG("kim.jpeg") to read in a jpeg file, but R gave me an > >error: > >Error in readJPEG("kim.jpeg") : unable to open kim.jpeg > > > >I already put "kim.jpeg" in Rstudio's default working directory: > >"E:\home > >work\Rstudio". So I don't think it's a problem caused by omitting the > >file's > >path. But I tried with the full path version just in case and still got > >the > >"unable to open" error: > > > >kim<-readJPEG("E:\\ home work\\Rstudio\\kim.jpeg") > >Error in readJPEG("E:\\ home work\\Rstudio\\kim.jpeg") : > > unable to open E:\ home work\Rstudio\kim.jpeg > > > >So now I really don't know what is wrong. > > > > [[alternative HTML version deleted]] > > > >______________________________________________ > >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. ______________________________________________ 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.