From hb at stat.berkeley.edu  Thu Mar  6 02:56:27 2008
From: hb at stat.berkeley.edu (Henrik Bengtsson)
Date: Wed, 5 Mar 2008 17:56:27 -0800
Subject: [Rd] invalid regular expression '[a-Z]'
Message-ID: <59d7961d0803051756s307dcab1kbaffc4eeb9d308cf@mail.gmail.com>

Hi,

just curious, but does anyone know the source/reason of observing the
following error on OSX but not on WinXP and Linux?  I've tried with a
few different versions of R (v2.5.1, v2.6.1, v2.6.2, v2.7.0devel).
The locale does not seem to affect the error, i.e. I've tested a few
different and it is still only OSX that gives the error but not the
other two.

> regexpr("[a-Z]", "foo")
Error in regexpr(pattern, text, extended, fixed, useBytes) :
        invalid regular expression '[a-Z]'
> regexpr("[a-zA-Z]", "foo")
[1] 1
attr(,"match.length")
[1] 1
> regexpr("[A-z]", "foo")
[1] 1
attr(,"match.length")
[1] 1

At least now I know it that the safest is to use '[a-zA-Z]' (or
possibly '[[:alpha:]]').

/Henrik



[Rd] invalid regular expression '[a-Z]'
Henrik Bengtsson