Re: 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(dot)(dot)$m+1]=(at)arr[$n(dot)(dot)$m];$arr[$n]=$x;

or:

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

gnari