Posted by Justin Koivisto on 02/04/06 01:01

comp.lang.php wrote:
> [PHP]
> $orderBy = 's.app_date desc, s.last_name asc, s.first_name asc, s.mi
> asc';
> if ($_REQUEST['willDesc']) {
> $ascArray = array('asc' => 'desc', 'desc' => 'asc'); // ARRAY OF
> ALL ORDERING POSSIBILITIES
> $junk = preg_match('/([\s\t]+)a|[de]sc(,?.*$)/i', $orderBy,
> $matchArray);
> $orderBy = substr($orderBy, 0, strpos($orderBy, $matchArray[1])) .
> ' ' . $ascArray[$matchArray[1]] .
> substr($orderBy, strpos($orderBy, $matchArray[1]) +
> strlen($matchArray[1]), strlen($orderBy));
> }
> [/PHP]
>
> Basic premise:
>
> I have a SQL "ORDER BY" clause that will be configured like $orderBy 's
> value. However, the very first occurrence of "desc" might instead be
> "asc". If the very first occurrence is "asc", it must become "desc";
> likewise, if the very first occurrence is "desc", it must become "asc".
>
> I tried Regular Expressions but the pattern failed every single time to
> match and replace, so I gave up and tried a string function/RegExp code
> combination, also to no avail.
>
> I am not sure how to make this work so I need help figuring out how to
> do this.
>
> Thanx
> Phil
>


function change_first_order_flag($orderBy){
$tmp = explode(
'__SPLIT__HERE__',
preg_replace(
'`(asc|desc)`i',
'__SPLIT__HERE__$1',
$orderBy
)
);

if(count($tmp)>1){
// there are at least 2 elements
// therefore, it was in there at least once
if(substr($tmp[1],0,3)=='des'){
// it was in descending order
$tmp[1]='as'.substr($tmp[1],3);
}else{
// it was in ascending order
$tmp[1]='des'.substr($tmp[1],3);
}
}

return join($tmp);
}


--
Justin Koivisto, ZCE - justin@koivi.com
http://koivi.com

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