array_walk_recursive Apply a user function recursively to every member of an array &reftitle.description; boolarray_walk_recursive arrayarray callablecallback mixeduserdata&null; Applies the user-defined callback function to each element of the array. This function will recurse into deeper arrays. &reftitle.parameters; array The input array. callback Typically, callback takes on two parameters. The array parameter's value being the first, and the key/index second. If callback needs to be working with the actual values of the array, specify the first parameter of callback as a reference. Then, any changes made to those elements will be made in the original array itself. userdata If the optional userdata parameter is supplied, it will be passed as the third parameter to the callback. &reftitle.returnvalues; &return.success; &reftitle.examples; 'apple', 'b' => 'banana'); $fruits = array('sweet' => $sweet, 'sour' => 'lemon'); function test_print($item, $key) { echo "$key holds $item\n"; } array_walk_recursive($fruits, 'test_print'); ?> ]]> &example.outputs; You may notice that the key 'sweet' is never displayed. Any key that holds an array will not be passed to the function. &reftitle.seealso; array_walk &seealso.callback;