Re: sort array optimisation in pl/perl

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От Ragnar Hafstað
Тема Re: sort array optimisation in pl/perl
Дата
Msg-id 1111697586.1995.17.camel@localhost.localdomain
обсуждение исходный текст
Ответ на sort array optimisation in pl/perl  ("GIROIRE Nicolas (COFRAMI)" <nicolas.giroire@airbus.com>)
Список pgsql-general
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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