Unix tools (was: [R] read data into R with some constraints)

[Prof Brian D Ripley]

On Fri, 12 Jan 2001, Clive Jenkins wrote:

>
> Thu, 11 Jan 2001 14:51:16 -0500 (EST) Jonathan Baron wrote:
> >
> > >I have a big data file (over 30,000 records) looks
> > >like this:
> > >
> > >100, 20, 46, 70
> > >103,  0, 22, 45
> > >117, -1, 34, 65
> > >120, 15,  0, 25
> > >113,  0,  -1, 32
> > >142, -1, -1, 55
> > >.....
> > >
> > >I want to read only those records having positive
> > >values in all of the  four
> > >columns. That is, I don't want to read record # 3, 5,
> > >and 6 into R.
> >
> > Perhaps someone knows how to do this with R, but, if
> > I had to do it right now, I would pre-process with grep
> > before reading into R:
> >
> > grep -v "-" myddata > myshorterdata
> >
> > The "grep" tool is available on Unix and Linux.  If you have
> > Windows, it would be useful to get the "unix tools for windows",
> > which, unfornuately, I have just been unable to find after 10
> > minutes of searching www.gnu.org.
>
> I recommend the DJGPP (DOS/DPMI) ports of the Gnu tools available at
> http://www.delorie.com/
> They are absolute magic for anybody who is frustrated by Windows and has
> not yet moved to Gnu/Linux. I find "gawk" (or "awk") especially useful.

Can I emphatically *not* recommend those, but the genuine Windows ones at
http://www.cygwin.com instead?  Particularly if you have NT/2000 and NTFS
file systems.  The DJGPP tools have frustrating limitations (e.g. on line
lengths) even for Win95 users.  And DJ Delorie works for Cygwin anyway.

As I posted earlier, a subset of the Cygwin tools and some others
have been collected for building R, at

http://www.stats.ox.ac.uk/pub/Rtools

We keep these up to date, but not in the (common) cases where the latest
versions are broken.  What is there will have built R in the last few days.

There quite a few other Unix-alike tool sets around, but none that
I have found anything like as good.


-- 
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

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