The printout of the program above will be:
?php $fruits = array ("d"= "citron", "a"= "orange", "b"= "banane", "c"= "pomme"); function test_alter ($item1, $key, $prefix) {$item1 = "$prefix: $item1";} function test_print ($item2, $key) {echo "$key. $item2 br \n";} array_walk ($fruits, 'test_print'); reset ($fruits); array_walk ($fruits, 'test_alter', 'fruit'); reset ($fruits); array_walk ($fruits, 'test_print');?