(3.0.4 - 3.0.18 only, PHP 4 >= 4.0.0)uasort -- Sort an array with a user-defined comparison function and maintain index association
This function sorts an array such that array indices maintain their correlation with the array elements they are associated with. This is used mainly when sorting associative arrays where the actual element order is significant. The comparison function is user-defined.
Note: Instead of a function name, an array containing an object reference and a method name can also be supplied.