From: | Doug Gorley <doug(dot)gorley(at)gmail(dot)com> |
---|---|
To: | pgsql-general(at)postgresql(dot)org |
Subject: | Regexp confusion |
Date: | 2009-10-09 21:36:46 |
Message-ID: | 4ACFACEE.8050001@gmail.com |
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Thread: | |
Lists: | pgsql-general |
Trying to match some numbers, and I'm having some regexp problems. I've
boiled it down to the following:
/* (1) */ select '3.14' similar to E'^\\d+\\.\\d+$'; -- true
/* (2) */ select '3.14' similar to E'^\\d+(\\.\\d+)$'; -- true
/* (3) */ select '3.14' similar to E'^\\d+(\\.\\d+)*$'; -- true
/* (4) */ select '3.14' similar to E'^\\d+(\\.\\d+)?$'; -- false
/* (5) */ select '3.14' similar to E'^\\d+(\\.\\d+)+$'; -- true
So, based on (1) and (2), the pattern '\.\d+' occurs once. So why does
(4) return false? between (3), (4), and (5), it appears as though the
group is matching multiple times.
Thanks,
--
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*Doug Gorley* | doug(dot)gorley(at)gmail(dot)com <mailto:doug(dot)gorley(at)gmail(dot)com>
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