(3.0.4 - 3.0.18 only, PHP 4 >= 4.0.0)uksort -- Sort an array by keys using a user-defined comparison function
This function will sort the keys of an array using a user-supplied comparison function. If the array you wish to sort needs to be sorted by some non-trivial criteria, you should use this function.
This example would display:
20: twenty 10: ten 4: four 3: three
Note: Instead of a function name, an array containing an object reference and a method name can also be supplied.