Re: sort array optimisation in pl/perl - Mailing list pgsql-general

From GIROIRE Nicolas (COFRAMI)
Subject Re: sort array optimisation in pl/perl
Date
Msg-id 1904E3EB39448246A7ECB76DF34A70B0036A401C@TOCOMEXC03
Whole thread Raw
In response to sort array optimisation in pl/perl  ("GIROIRE Nicolas (COFRAMI)" <nicolas.giroire@airbus.com>)
Responses Re: sort array optimisation in pl/perl
List pgsql-general

Hi,

thanks for this help.

The method functions great but the profit of time is good just if I have a lot of elements to deplace.

        COFRAMI
        Nicolas Giroire
        on behalf of AIRBUS France
        for In Flight & Ground Information Services - Development
        Phone : +33 (0)5 67 19 98 74
              Mailto:nicolas.giroire@airbus.com

-----Message d'origine-----
De : pgsql-general-owner@postgresql.org
[mailto:pgsql-general-owner@postgresql.org]De la part de Ragnar Hafstað
Envoyé : jeudi 24 mars 2005 21:53
À : GIROIRE Nicolas (COFRAMI)
Cc : 'pgsql-general@postgresql.org'
Objet : Re: [GENERAL] sort array optimisation in pl/perl

On Thu, 2005-03-24 at 15:49 +0100, GIROIRE Nicolas (COFRAMI) wrote:

> I create an array which is result of query on postgresql database and
> then I want to sort rows in a particular way (impossible by query on
> database).

can you give us more details on this particular sort order?

> My solution consists to put a rows (indice m+1) in a temporary other
> and then move all element before indice n to m in rows with indice n+1
> to m+1 and last i put my temporary variable to indice n.
> I want to know if somebody know a better solution.
>
> I think of 2 solutions but i don't success to apply :
>   - the first is to use list in which I could deplace references as a
> chained list
>   - the second will be to deplace tab[n..m] to tab[n+1..m+1] in one
> instruction as ada language

it all depends on the expected sizes of your arrays, but perl has
some nice array operations, such as slices and splice()

these come to mind:

$x=$arr[$m+1];@arr[$n+1..$m+1]=@arr[$n..$m];$arr[$n]=$x;

or:

@arr[$n..$m+1]=($arr[$m+1],@arr[$n..$m]);

gnari

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