[TOC] ## 簡單demo ``` $sweet = array('a' => 'apple', 'b' => 'banana'); $fruits = array('sweet' => $sweet, 'sour' => 'lemon'); function test_print(&$item, $key) { $item = "$key holds $item\n"; } array_walk_recursive($fruits, 'test_print'); var_export($fruits); /* [ 'sweet' => [ 'a' => 'a holds apple ', 'b' => 'b holds banana ', ], 'sour' => 'sour holds lemon ', ]; */ ```