Compare the keys and values of three arrays with a user-defined function to compare keys, return matches in PHP

/* www .  j a va  2 s  . c  o  m*/
<?php
function myfunction($a,$b){
   if ($a===$b){
     return 0;
   }
   return ($a>$b)?1:-1;
}

$a1=array("a"=>"red","b"=>"green","c"=>"blue");
$a2=array("a"=>"red","b"=>"Basic","d"=>"blue");
$a3=array("e"=>"yellow","a"=>"red","d"=>"blue");

$result=array_intersect_uassoc($a1,$a2,$a3,"myfunction");
print_r($result);
?>