## Example

`

     array array_diff_ukey ( array $array1 , array $array2 [, array $ ... ], callback $key_compare_func )

`

## Description

Compares the keys from array1 against the keys from array2 and returns the difference. This function is like array_diff() except the comparison is done on the keys instead of the values. Unlike array_diff_key() an user supplied callback function is used for the indices comparison, not internal function.

## Return Values

Returns an array containing all the entries from array1 that are not present in any of the other arrays.