Date: Wed, 12 Sep 2007 08:52:03 -0400
From: Alvaro Herrera <alvherre@commandprompt.com>
To: Paul Lambert <paul.lambert@autoledgers.com.au>
Cc: sql pgsql <pgsql-sql@postgresql.org>
Subject: Re: Extracting hostname from URI column
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Paul Lambert wrote:
> Andrej Ricnik-Bay wrote:
>
>> Plain regex.... The key are the parenthesis () ...
>> basically it will omit ANYTHING + two slashes at the beginning
>> of a string.  Then it will match everything BUT a slash, and as
>> much of that as possible since regex are greedy by default
>> (hence the host name he was looking for) ... and everything
>> AFTER a slash will be omitted.
>> Cheers,
>> Andrej
> Thanks - that makes a bit more sense. I'm in the middle of reading chapter 
> 9.3.7 of the manual - POSIX Regular Expressions - which I'm assuming is 
> dealing with this, so it's looking clearer.

A very good resource on regular expressions is "Mastering Regular
Expressions" by Jeffrey Friedl, now in its third edition:
http://www.oreilly.com/catalog/regex3/

I read the first ed. years ago and it was very illuminating.

-- 
Alvaro Herrera                          Developer, http://www.PostgreSQL.org/
"Acepta los honores y aplausos y perderás tu libertad"