Thanks so much!
On Sat, Jul 28, 2012 at 1:32 PM, Ted Harding <ted.hard...@wlandres.net> wrote: > And, in addition to the tip from Rui (and similar from Joshua) below, > I would advise that there is one good reason not to try doing it > in "pure Linux". > > The only source (that I know of) in Linux itself for random numbers > can be tapped by something like > > cat /dev/random > filename > > /dev/random stores noise generated by the timings of system events > (keyboard presses, mouse-clicks, disk accesses, interrupts, etc.) > after subjecting them to a high-entropy stirring process. See: > > man random > > It yields them in the form of random bytes (each of 8 random 0/1 bits) > and you would have to devise some means of coverting those onto a > form suitable for accessing a directory listing at random. Not a > pretty task! > > There is also the command 'rand' available in the openSSL toolkit, > but that still outputs the results in the same format as /dev/random. > > If you really want to do this outside R, the I would suggest writing > a little C program (to be run from the Linux command line). C can > do its own random number generation, with results returned as > real (double), and then apply these to select at random from the > contents of a file generated by something like > > ls filesdir > filelist.txt > > and output the random selection. > > Ted. > > On 28-Jul-2012 18:00:38 Rui Barradas wrote: >> Hello, >> >> If the files are to be processed in R select a random sample in R. >> Using list.files() you can assign a character vector with the filenames >> of interest and then sample from that vector. >> >> ?list.files >> filenames <- list.files(path, pattern) >> >> rand.sampl <- sample(filenames, 45) >> >> Hope this helps, >> >> Rui Barradas >> >> Em 28-07-2012 18:49, Erin Hodgess escreveu: >>> Dear R People: >>> >>> I am using a Linux system in which I have about 3000 files. >>> >>> I would like to randomly select about 45 of those files to be processed in >>> R. >>> >>> Could I make the selection in R or should I do it in Linux, please? >>> >>> This is with R-2.15.1. >>> >>> Thanks, >>> erin >>> >>> >> >> ______________________________________________ >> 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. > > ------------------------------------------------- > E-Mail: (Ted Harding) <ted.hard...@wlandres.net> > Date: 28-Jul-2012 Time: 19:32:26 > This message was sent by XFMail > ------------------------------------------------- -- Erin Hodgess Associate Professor Department of Computer and Mathematical Sciences University of Houston - Downtown mailto: erinm.hodg...@gmail.com ______________________________________________ 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.
