Naoki Takebayashi
2002-Dec-07 22:01 UTC
[R] bugs in system() handling long character strings??
Hi, system(cmd, intern=T) seems to have a problem when cmd returns a long character string. For example, if a file (/tmp/long.txt) contains a long string such as: 123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890 There are 120 characters in this one line.> junk <- system("cat /tmp/long", TRUE) > junk[1] "1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678" [2] "0"> nchar(junk[1])[1] 118 So one long line get separated into two parts, and additionally 119-th character is missing. Is this a bug in R or am I missing something? I tried this on R-1.6.1 on linux/alpha and linux/i386. Thanks, Naoki Naoki Takebayashi <ntakebay at bio.indiana.edu> --- Dept. of Biology, Box 90338, Duke University, Durham, NC 27708-0338
ripley@stats.ox.ac.uk
2002-Dec-07 23:51 UTC
[R] bugs in system() handling long character strings??
There is an undocumented limit of 119 characters/line when using system(intern=TRUE) on Unix. You can easily raise it: it is in do_system in file src/unix/sys-unix.c. I think this limit should be raised considerably, but it may well not be worth eliminating it. On Sat, 7 Dec 2002, Naoki Takebayashi wrote:> Hi, > > system(cmd, intern=T) seems to have a problem when cmd returns a long > character string. > > For example, if a file (/tmp/long.txt) contains a long string such as: > > 123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890 > > There are 120 characters in this one line. > > > junk <- system("cat /tmp/long", TRUE) > > junk > [1] "1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678" > [2] "0" > > nchar(junk[1]) > [1] 118 > > So one long line get separated into two parts, and additionally 119-th > character is missing. > > Is this a bug in R or am I missing something? > > I tried this on R-1.6.1 on linux/alpha and linux/i386. > > Thanks, > Naoki > > Naoki Takebayashi <ntakebay at bio.indiana.edu> > --- Dept. of Biology, Box 90338, Duke University, Durham, NC 27708-0338 > > ______________________________________________ > R-help at stat.math.ethz.ch mailing list > http://www.stat.math.ethz.ch/mailman/listinfo/r-help >-- Brian D. Ripley, ripley at stats.ox.ac.uk 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 272860 (secr) Oxford OX1 3TG, UK Fax: +44 1865 272595