    array_walk_recursive (PHP 5, PHP 7, PHP 8)
array_walk_recursive — Apply a user function recursively to every member of an array   Description array_walk_recursive(array|object &$array, callable $callback, mixed $arg = null): bool  Applies the user-defined callback function to each element of the array. This function will recurse into deeper arrays.    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.  
Note: 
 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.     arg
   If the optional arg parameter is supplied, it will be passed as the third parameter to the callback.      Return Values  Returns true on success or false on failure.    Examples
 Example #1 array_walk_recursive() example  <?php
$sweet = array('a' => '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');
?>  The above example will output:  
a holds apple
b holds banana
sour holds lemon
   You may notice that the key 'sweet' is never displayed. Any key that holds an array will not be passed to the function.     See Also
 array_walk() - Apply a user supplied function to every member of an array   


    
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