Problem With Sorting array

If Array Keys Are Same . then Values added one by one based on comma  .

It sounds like you mean to "merge" arrays, not to sort.

PHP Code:

$a1 = array('10' => 12);
$a2 = array('10' => 7, '4' => 7);

$out = $a1;
foreach($a2 as $key => $value)
{
 if(array_key_exists($key, $out))
 {
 $out[$key] .= ",".$value;
 }
 else
 {
 $out[$key] = $value;
 }
}

print_r($out); 


Thanks For U r Answer ..
But each every time Arrays changed .. Some times I am Getting Only One Array . Some Times Two , Some Times Four .. These arrays Dynamically generated .. On that Time...?

Manikanta