Tanx for your help Dan,
I think i have found a good solution :
template code (parsing php on input):
{exp:channel:entries channel="chroniques" limit="18" orderby="random" search:mag-chronique="{no_mag_sum}" status="open|Cover|Vedette" }
{/exp:channel:entries}
Snipet {no_mag_sum} :
<?php
$arr_magno = array(
array( 'no' => 79, 'kiosque' => "2010-12-02"),
array( 'no' => 80, 'kiosque' => "2011-01-13"),
array( 'no' => 81, 'kiosque' => "2011-02-17"),
array( 'no' => 82, 'kiosque' => "2011-03-17"),
array( 'no' => 83, 'kiosque' => "2011-04-21"),
array( 'no' => 84, 'kiosque' => "2011-05-19"),
array( 'no' => 85, 'kiosque' => "2011-06-16"),
array( 'no' => 86, 'kiosque' => "2011-07-21"),
array( 'no' => 87, 'kiosque' => "2011-08-25"),
array( 'no' => 88, 'kiosque' => "2011-09-23"),
array( 'no' => 89, 'kiosque' => "2011-10-27"),
array( 'no' => 90, 'kiosque' => "2011-12-01")
);
$arr_magno = array_reverse($arr_magno);
foreach ($arr_magno as &$value) {
if (strtotime($value['kiosque']) <= strtotime("now")){
echo $value['no'];
break;
}
}
?>
So the snippet is process firt (expand), then the PHP is parsed and finaly the channel module.
So solution found, you can close this topic if you want