Re: Number of occurrence of characters?

From: Ivan Voras <ivoras(at)freebsd(dot)org>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: Number of occurrence of characters?
Date: 2009-02-06 09:42:27
Message-ID: gmh0me$3of$1@ger.gmane.org
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hubert depesz lubaczewski wrote:
> On Thu, Feb 05, 2009 at 02:31:24PM +0100, Ivan Voras wrote:
>> The problem is how to do it efficiently. I see there isn't a built-in
>> function that counts character occurrences so I'd have to write it
>> myself. An additional constraint is that it must be implemented with
>> built-in capabilities, i.e. SQL and plpsql languages. I can do it the
>> brute force way, looping over the string and processing one by one
>> character with substring(), but is there a faster way?
>
> # select length(regexp_replace('/some/string/with/slashes', '[^/]+', '', 'g'));
> length
> --------
> 4
> (1 row)

Thank you (and Heikki), I had a feeling I was missing an approach.

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