Subject: Re: Isnumeric function?
From: Oliver Elphick <olly@lfix.co.uk>
Reply-To: olly@lfix.co.uk
To: Josh Berkus <josh@agliodbs.com>
Cc: Theo Galanakis <Theo.Galanakis@lonelyplanet.com.au>,
	pgsql-sql@postgresql.org
In-Reply-To: <200409081048.01034.josh@agliodbs.com>
References: <82E30406384FFB44AFD1012BAB230B55037D056E@shiva.au.lpint.net>
	<200409080947.17682.josh@agliodbs.com> <1094664017.2014.80.camel@linda>
	<200409081048.01034.josh@agliodbs.com>
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Organization: LFIX Limited
Message-Id: <1094667111.2014.98.camel@linda>
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Date: Wed, 08 Sep 2004 19:11:51 +0100
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On Wed, 2004-09-08 at 18:48, Josh Berkus wrote:
> Theo, Oliver,
> 
> > Any reason why you don't like  ~ '^([0-9]?)+\.?[0-9]*$' ?
> 
> Yes, because it also matches "." , which is not a valid numeric value.
> 
> >  ~ '^([0-9]+|[0-9]+\\.[0-9]*|[0-9]*\\.[0-9]+)$'
> 
> Ah, the brute force approach ;-)

Nothing like using a nice big hammer!

> Actually, the above could be written:
> 
> ~ '^([0-9]+)|([0-9]*\\.[0-9]+)$'

But that doesn't allow a trailing decimal point.

> 
> ... though that still seems inelegant to me.  Is there a regex expert in the 
> house?

All the elegant approaches I can think of match the empty string. There
must be at least one digit and 0 or 1 decimal point with no other
characters permitted.  If you use this as a constraint, you could make
it elegant and combine it with another constraint to exclude '' and '.'.
-- 
Oliver Elphick                                          olly@lfix.co.uk
Isle of Wight                              http://www.lfix.co.uk/oliver
GPG: 1024D/A54310EA  92C8 39E7 280E 3631 3F0E  1EC0 5664 7A2F A543 10EA
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