Re: Request to add feature to the Position function

From: Brian Dunavant <brian(at)omniti(dot)com>
To: Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com>
Cc: Ron Ben <ronb910(at)walla(dot)co(dot)il>, "pgsql-general(at)postgresql(dot)org" <pgsql-general(at)postgresql(dot)org>
Subject: Re: Request to add feature to the Position function
Date: 2017-03-27 16:03:12
Message-ID: CAJTy2e=VbFWo3Wrfv57X3w9FzYvVbG-ShxAnqi7v5D9ju=tWnA@mail.gmail.com
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That does not return the correct answer for the original poster's request.

flpg=# select position('om' in reverse('Tomomasaaaaaaaaaaa'));
position
----------
15
(1 row)

On Mon, Mar 27, 2017 at 11:43 AM, Adrian Klaver
<adrian(dot)klaver(at)aklaver(dot)com> wrote:
> On 03/27/2017 08:05 AM, Ron Ben wrote:
>>
>> Hi,
>> position(substring in string)
>> as listed here:
>> https://www.postgresql.org/docs/9.1/static/functions-string.html
>> locates sub string in a string.
>>
>> It doesn't support locateing the substring from the back.
>>
>> For example:
>>
>> position('om' in 'Tomomas')
>> gives 2
>>
>> But if I want to locate the first occurance from the back of the string
>> it's impossible/
>
>
> aklaver(at)test=> select position('om' in reverse('Tomomas'));
> position
> ----------
> 4
>
>
>>
>> My suggestion is to create a function
>> position(substring in string,order)
>> where order can be: begin, end
>>
>> and it will find the string according to this parameter.
>> This is pretty easy to implement and should be a part of the PostgreSQL
>> tools.
>>
>> similar fuctionality exists in trim function where user can specify
>> leading or taling parameter
>
>
>
> --
> Adrian Klaver
> adrian(dot)klaver(at)aklaver(dot)com
>
>
> --
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