PHP, associative array, delete elements based on element value

After some modifications and improvements, the effect

$array1 = array("a" => "green", "red", "blue", "red");
$array2 = array("b" => " green");
$result = array_diff($array1, $array2);//This is equivalent to deleting the element with the value "green" in $array1.
print_r($result);
?>
/* There is another method, which is more complicated than the above, but the effect is the same. */
 removefunctionArrayElement(&$ar,$val)
{
$tmp = array();
foreach($ar as $k => $arc)
{
 if($arc!=$val)
 {
 $tmp[$k]=$arc;
 }
}
$ar = $tmp;
unset($tmp);
}