(PHP 3>= 3.0.4, PHP 4 )
uasort -- Sort an array with a user-defined comparison function and maintain index associationThis 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.
See also: usort(), uksort(), sort(), asort(), arsort(), ksort() and rsort().