[R] help with grep list files

David Wolfskill r at catwhisker.org
Mon Feb 20 22:57:10 CET 2017

On Mon, Feb 20, 2017 at 03:41:50PM -0600, Glenn Schultz wrote:
> All,
> I have the following files in a directory and I would like only a list of those starting with “lld" and ending with “dat”.  I used the following and it gives me the lld files 
>  list.files(path = readpath, pattern = "^lld[A-Z0-9]")
> to get just .dat files I tried
>  list.files(path = readpath, pattern = "^lld[A-Z0-9].dat$”) but nothing is returned
> below is a dput from the first command.  $ is an end of line anchor correct?  What am I doing wrong?

Note that help(list.files) mentions (among other things):

| Note:
|      File naming conventions are platform dependent.  The pattern
|      matching works with the case of file names as returned by the OS.

Also, your pattern ("^lld[A-Z0-9].dat$") does not include the '_'

I was able to get the results you requested in my environment (FreeBSD
stable/11) using:

list.files(path = readpath, pattern = "^lld[_A-Z0-9]*.dat$")

(Note the '*' in there, as well.)

But "filename globbing" is not the same as "regular expressions," and as
the above-cited Note warns, results may well be platform-dependent, so
be careful.

> Best,
> Glenn
> .... 

David H. Wolfskill				r at catwhisker.org
How could one possibly "respect" a misogynist, racist, bullying con-man??!?

See http://www.catwhisker.org/~david/publickey.gpg for my public key.
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