Prof Brian Ripley <ripley at stats.ox.ac.uk> wrote:
Peter J. Acklam wrote:
Marcelo Luiz de Laia wrote:
files <- dir(pattern="*.sens")
That's not even a valid regular expression in most applications, but "dir" does allow it, for some reason. Anyway, I think you
It is a valid regex in GNU's regex code as used by R, and all the GNU and non-GNU applications I tried accepted it. `*' matches itself when not used as a repetition qualifier. (I tried several greps, including those claiming strict POSIX compliance.) So, can you please list the `most applications' you tried or give a reference for your assertion?
I should have said "many applications", not "most applications." I use Solaris, and I don't know one Solaris application which allows it, including egrep, oawk, and nawk. And no version of Perl allows it. GNU-tools allow it, but in an inconsistent way. GNU Emacs treats `*x' as `\*x' (match a literal star and a literal x), but GNU grep (version 2.5) treats `*x' as `.*x' (match anything up to and including the first x), which is something quite different. It's a mess, it's inconsistent, and it's not portable. I suggest people stop using "*..." and use "\*..." or ".*..." depending on what is wanted. Peter
Peter J. Acklam - pjacklam at online.no - http://home.online.no/~pjacklam