R help - May 2014 - regexec: Unexpected answer when matching digits

I was trying to use regexec to extract number fields from my data and got an
unexpected response.  I can reproduce the issue with this small test case.

regexec("\\d{2,}", "abcd123")

I get a match at position 1, for length 7.  Not what I expected.

I do get the expected response (match at position 5, for length 3) when I do any
of the following:

regexec("[0-9]{2,}", "abcd123")
regexec("\\d{1,}", "abcd123")
regexec("\\d+", "abcd123")

I have also verified that regexpr handles this pattern as I expect.

And to add further confusion, this only seems to happen on my Linux machine, not
on Windows.

This seems to be an incredibly specific condition.  Anybody know what's
going on?

-- 
Steve Sentoff

On 04/05/2014, 5:03 PM, Stephen Sentoff wrote:
> I was trying to use regexec to extract number fields from my data and got
an unexpected response.  I can reproduce the issue with this small test case.
>
> regexec("\\d{2,}", "abcd123")
>
> I get a match at position 1, for length 7.  Not what I expected.
>
> I do get the expected response (match at position 5, for length 3) when I
do any of the following:
>
> regexec("[0-9]{2,}", "abcd123")
> regexec("\\d{1,}", "abcd123")
> regexec("\\d+", "abcd123")
>
> I have also verified that regexpr handles this pattern as I expect.
>
> And to add further confusion, this only seems to happen on my Linux
machine, not on Windows.
>
> This seems to be an incredibly specific condition.  Anybody know what's
going on?
>
It looks like a bug.  I see it in R 3.0.3 on Mac OS, but not in 
3.1.0-patched on Windows.  What version are you using, on what OS?

Duncan Murdoch