Description
array 
array_diff ( array array1, array array2 [, array ...] )
     array_diff() returns an array
     containing all the values of array1
     that are not present in any of the other arguments.
     Note that keys are preserved.
    
     
Example 1. array_diff() example 
<?php $array1 = array("a" => "green", "red", "blue", "red"); $array2 = array("b" => "green", "yellow", "red"); $result = array_diff($array1, $array2);
  print_r($result); ?>
 |  
 
       Multiple occurrences in $array1 are all treated the same way.
       This will output :
        | 
    Note: 
      Two elements are considered equal if and only if
      (string) $elem1 === (string) $elem2. In words:
      when the string representation is the same.
      
     
Note: 
      Please note that this function only checks one dimension of a n-dimensional
      array. Of course you can check deeper dimensions by using
      array_diff($array1[0], $array2[0]);.
     
| Warning | 
      This was broken in PHP 4.0.4!
      
       | 
     See also array_diff_assoc(),
     array_intersect(), and
     array_intersect_assoc().