$fruits = array ("d"=>"lemon", "a"=>"orange", "b"=>"banana", "c"=>"apple");
function test_alter (&$item1, $key, $prefix) {
$item1 = "$prefix: $item1";
}
function test_print ($item2, $key) {
echo "$key. $item2
\n";
}
array_walk ($fruits, 'test_print');
reset ($fruits);
array_walk ($fruits, 'test_alter', 'fruit');
reset ($fruits);
array_walk ($fruits, 'test_print');
?>