PHP 中的 array_udiff()函数

<?php
   function call_back_function($v1,$v2) {
      if ($v1 === $v2) {
         return 0;
      }
      return 1;
   }
   $array1=array("a"=>"orange","b"=>"mango","c"=>"banana");
   $array2=array("a"=>"orange","b"=>"mango","c"=>"apple");
   
   print_r(array_udiff_assoc($array1,$array2,"call_back_function"));
?>