PHP Array with dynamic Name

[Justin Bennett]

I have a PHP array with a dynamic name.
$$cat

It's getting built by a result from a query against an orable DB. I want 
to look through this array and replace any 0 with a null value. so I can 
pass this array to JpGraph and not plot zeros. I try looking through with

foreach ($$cat as $k => $v {
if ($v == 0) {
$$cat[$k] = "";
}
}
It doesn't work, It doesn't place the values back in the array I believe 
because its has a dynamic name. Any ideas?


Thanks
Justin