invalid regular expression '[a-Z]'

On Wed, Mar 5, 2008 at 6:18 PM, Duncan Murdoch <murdoch at stats.uwo.ca> wrote:
 > On 05/03/2008 8:56 PM, Henrik Bengtsson wrote:
 >  > Hi,
 >  >
 >  > just curious, but does anyone know the source/reason of observing the
 >  > following error on OSX but not on WinXP and Linux?
 >
 >  Presumably in the locale you're using on OSX, "a" < "Z" is false.  This
 >  is the ascii sort order used in the C locale.  On my Windows box, "a" <
 >  "Z" is true, because it uses the English_Canada.1252 collation order.
 That's it indeed.  The person who first reported the error had
 sessionInfo() locale
 'en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8' and I
 missed that 'C' in the middle, which I guess his system falls back to
 if none of the previous ones exist?!?

 Now I can reproduce it on both Windows and Linux:

 > Sys.setlocale("LC_ALL", "C")
 [1] "C"
 > regexpr("[a-Z]", "foo")
 Error in regexpr("[a-Z]", "foo") : invalid regular expression '[a-Z]'
 > Sys.setlocale("LC_ALL", "en")
 [1] "LC_COLLATE=English_United States.1252;LC_CTYPE=English_United States.1252;L
 C_MONETARY=English_United States.1252;LC_NUMERIC=C;LC_TIME=English_United States
 .1252"
 > regexpr("[a-Z]", "foo")
[1] 1
 attr(,"match.length")
 [1] 1

 Case almost closed, but then the question is why don't you get an
 error in one of the two cases '[a-Z]' and '[A-z]' then with the other
 locale(s)?

 > Sys.setlocale("LC_ALL", "en")
 [1] "LC_COLLATE=English_United States.1252;LC_CTYPE=English_United States.1252;L
 C_MONETARY=English_United States.1252;LC_NUMERIC=C;LC_TIME=English_United States
 .1252"
 > regexpr("[a-Z]", "foo")
[1] 1
 attr(,"match.length")
 [1] 1
 > regexpr("[A-z]", "foo")
 [1] 1
 attr(,"match.length")
 [1] 1
 > "a" < "Z"
 [1] TRUE
 > "a" > "Z"
 [1] FALSE
My bad...
"A" < "z"
[1] TRUE
 > regexpr("[A-z]", "foo")
 [1] 1
 attr(,"match.length")
 [1] 1
"z" < "A"
[1] FALSE
regexpr("[z-A]", "foo")
Error in regexpr("[z-A]", "foo") : invalid regular expression '[z-A]'

Case closed

/Henrik
 Thanks

 /Henrik

 >
 >  Duncan Murdoch
 >
 >
 >   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
 >  >
 >  > ______________________________________________
 >  > R-devel at r-project.org mailing list
 >  > https://stat.ethz.ch/mailman/listinfo/r-devel
 >
 >

invalid regular expression '[a-Z]'

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