APPLY Apply a user supplied function to every member of an ARRAY, recursively.
<?php
bool array_walk_recursive ( arr &$array , callable $callback [,
mix $userdata = NULL ] )
where,
&$array = The input ARRAY
$callback = The function to be used as the user-defined function
$userdata = The third parameter to be passed to the callback function
?>
EXERCISE
<?php
function comp01($val01, $key01, $nmr01)
{
echo $nmr01 . ' ' . $val01 .
' (' . $key01 . ')<br>';
}
$arr01 = [ "R" => "RED",
"G" => "GREEN",
"B" => "BLUE",
"WHITE" => [ 255,255,255 ] ];
echo '<pre>';
print_r($arr01);
echo '</pre>';
@array_walk($arr01, "comp01", "Component: ");
echo '<pre>';
print_r($arr01);
echo '</pre>';
echo '<br><br>';
@array_walk_recursive($arr01, "comp01", "Component: ");
echo '<pre>';
print_r($arr01);
echo '</pre>';
?>
EXERCISE
<?php
function foo($value) {
echo $value . " foo<br>";
}
function bar($value) {
echo $value . " bar<br>";
}
$arr = array (1,2,3);
var_dump (array_walk_recursive ($arr, 'foo'));
echo '<br><br>';
var_dump (array_walk_recursive ($arr, 'bar'));
?>
EXERCISE
<?php
echo "Testing array_walk_recursive() : basic functionality.";
// regular array
$fruits = array("lemon", array("orange", "banana"),
array("apple"));
function test_print($item, $key)
{
// dump the arguments to check that they are passed
// with proper type
var_dump($item);
// value
var_dump($key);
// key
echo "<br><br>";
// new line to separate the
// output between each element
}
function with_userdata($item, $key, $user_data)
{
// dump the arguments
// to check that they are passed
// with proper type
var_dump($item);
// value
var_dump($key);
// key
var_dump($user_data);
// user supplied data
echo "<br><br>";
// new line to separate the
// output between each element
}
echo "<br><br><br>With default parameters
to show array contents:<br><br>";
var_dump( array_walk_recursive($fruits, 'test_print'));
echo "<br><br><br>With all parameters:<br><br>";
var_dump( array_walk_recursive($fruits,
'with_userdata',
"Added"));
?>
EXERCISE
<?php
echo "Testing array_walk_recursive() : basic functionality.";
// associative array
$fruits = array("a" => "lemon",
"b" => array( "c" => "orange",
"d" => "banana"),
"e" => array("f" => "apple"));
echo '<br><br>The given $fruits:<br>';
var_dump($fruits);
function test_alter(&$item, $key, $prefix)
{
// dump the arguments to check that they are passed
// with proper type
var_dump($item);
// value
var_dump($key);
// key
var_dump($prefix);
// additional argument passed
// to callback function
echo "<br><br>";
// new line to separate the
// output between each element
}
function test_print($item, $key)
{
// dump the arguments to
// check that they are passed
// with proper type
var_dump($item);
// value
var_dump($key);
// key
echo "<br><br>";
// new line to separate the
// output between each element
}
echo "<br><br><br>With default parameters
to show array contents:<br><br>";
var_dump(array_walk_recursive($fruits, 'test_print'));
echo "<br><br><br>With one optional parameter
to modify contents:<br><br>";
var_dump (array_walk_recursive($fruits, 'test_alter', 'fruit'));
echo "<br><br><br>With default parameters
to show modified array contents:<br><br>";
var_dump (array_walk_recursive($fruits, 'test_print'));
?>
EXERCISE
<?php
/*
* Testing array_walk_recursive()
* with following types of 'input' arrays:
* integer, float, string, bool,
* null, empty & mixed
*/
function print_value($value, $key, $count)
{
echo $count." : ".$key." ".$value."\n";
}
echo "With different values.";
// different arrays as input
$input_values = array(
// integer values
/*1*/ array(array(1, 0, -10), array(023, -041),
array(0x5A, 0X1F, -0x6E)),
// float value
array(array(3.4, 0.8, -2.9), array(6.25e2, 8.20E-3)),
// string values
array('Mango', array("Apple", 'Orange', "Lemon")),
// bool values
/*4*/ array( array(true, false), array(TRUE, FALSE)),
// null values
array( array(null), array(NULL)),
// empty array
array(),
// binary array
array(array(b'binary')),
// mixed array
/*8*/ array(16, 8.345, array("Fruits"),
array(true, null),
array(FALSE),
array(-98, 0.005, 'banana'))
);
for($count = 0; $count < count($input_values); $count++) {
echo "<br><br>Iteration: ".($count + 1)."<br>";
var_dump( array_walk_recursive($input_values[$count],
"print_value",
$count+1));
}
?>
EXERCISE
<?php
/*
* Testing array_walk_recursive()
* with an array having subarrays as elements
*/
echo "Testing array_walk_recursive() : array with subarray.<br><br>";
function callback($value, $key)
{
// dump the arguments to check that they are passed
// with proper type
var_dump($key);
// key
var_dump($value);
// value
echo "<br><br>";
// new line to separate the
// output between each element
}
$input = array(
array(),
array(1),
array(1,2,3),
array("Mango", "Orange"),
array(array(1, 2, 3), array(1))
);
var_dump( array_walk_recursive( $input, "callback"));
?>
EXERCISE
<?php
/*
* Testing array_walk_recursive()
* with an array having reference variables
*/
echo "Testing array_walk_recursive() : array with references.<br><br>";
$value1 = 10;
$value2 = -20;
$value3 = &$value1;
$value4 = 50;
// 'input' array containing references
// to above variables
$input = array(&$value1, array(&$value2, -35),
array(&$value3, 0),
array(&$value4));
function callback($value, $key)
{
// dump the arguments to check
// that they are passed
// with proper type
var_dump($key);
// key
var_dump($value);
// value
echo "<br><br>";
// new line to separate the
// output between each element
}
var_dump( array_walk_recursive($input, "callback"));
?>
EXERCISE
<?php
/*
* Passing 'input' argument
* as an associative array
* with Numeric & string keys
*/
echo "Testing array_walk_recursive() :
'input' as an associative array.";
function for_numeric($value, $key, $user_data)
{
// dump the input values to see if they are
// passed with correct type
var_dump($key);
var_dump($value);
var_dump($user_data);
echo "<br><br>";
// new line to separate the output
// between each element
}
function for_string($value, $key)
{
// dump the input values to see if they are
// passed with correct type
var_dump($key);
var_dump($value);
echo "<br><br>";
// new line to separate the output
// between each element
}
function for_mixed($value, $key)
{
// dump the input values
// to see if they are
// passed with correct type
var_dump($key);
var_dump($value);
echo "<br><br>";
// new line to separate the output
// between each element
}
// Numeric keys
$input = array( 0 => array(1 => 25, 5 => 12, 0 => -80),
1 => array(-2 => 100, 5 => 30));
echo "<br><br><br>Associative array with numeric keys:<br><br>";
var_dump( array_walk_recursive($input, "for_numeric", 10));
// String keys
$input = array( "a" => "Apple",
'z' => array('b' => 'Bananna', "c" => "carrot"),
'x' => array('o' => "Orange"));
echo "<br><br><br>Associative array with string keys:<br><br>";
var_dump( array_walk_recursive($input, "for_string"));
// binary key
$input = array( b"a" => "Apple", b"b" => "Banana");
echo "<br><br><br>Associative array with binary keys:<br><br>";
var_dump( array_walk_recursive($input, "for_string"));
// Mixed keys - numeric/string
$input = array( 0 => array(0 => 1, 1 => 2),
"x" => array("a" => "Apple", "b" => "Banana"),
2 =>3);
echo "<br><br><br>Associative array with numeric/string keys:<br><br>";
var_dump( array_walk_recursive($input, "for_mixed"));
?>
EXERCISE
<?php
/*
* Passing anonymous(run-time) callback
* function with following variations:
* with one parameter
* two parameters
* three parameters
* extra parameters
* without parameters
*/
echo "Testing array_walk_recursive() :
anonymous function as callback.";
$input = array( array(2, 5), array(10, 0));
echo "<br><br><br>With one argument:<br><br>";
var_dump( array_walk_recursive($input,
function($value) { var_dump($value);
echo "<br>"; }));
echo "<br><br><br>With two arguments:<br><br>";
var_dump( array_walk_recursive($input,
function($value, $key)
{ var_dump($key); var_dump($value);
echo "<br>"; }
));
echo "<br><br><br>With three arguments:<br><br>";
var_dump( array_walk_recursive($input, function($value,
$key, $user_data) { var_dump($key);
var_dump($value);
var_dump($user_data);
echo "<br>"; }, 10));
echo "<br><br><br>With null argument:<br><br>";
var_dump( array_walk_recursive( $input, function()
{ echo "1<br>"; }
));
?>
EXERCISE
<?php
/*
* Passing different types of callback
* functions to array_walk_recursive()
* without parameters
* with less and more parameters
*/
echo "Testing array_walk_recursive() :
callback function variation.";
$input = array(array('Apple', 'Banana'),
'Mango',
array('Orange'));
echo "<br><br><br>callback function
with both parameters:<br><br>";
function callback_two_parameter($value, $key)
{
// dump the arguments to check
// that they are passed
// with proper type
var_dump($key);
// key
var_dump($value);
// value
echo "<br><br>";
// new line to separate the
// output between each element
}
var_dump( array_walk_recursive($input,
'callback_two_parameter'));
echo "<br><br><br>callback function
with only one parameter:<br><br>";
function callback_one_parameter($value)
{
// dump the arguments to check
// that they are passed
// with proper type
var_dump($value);
// value
echo "<br><br>";
// new line to separate the
// output between each element
}
var_dump( array_walk_recursive($input,
'callback_one_parameter'));
echo "<br><br><br>callback function
without parameters:<br><br>";
function callback_no_parameter()
{
echo "<br><br><br>callback3() called:<br><br>";
}
var_dump( array_walk_recursive($input,
'callback_no_parameter'));
echo "<br><br><br>passing one more parameter
to function with two parameters:<br><br>";
var_dump( array_walk_recursive($input,
'callback_two_parameter',
10));
?>
EXERCISE
<?php
/*
* Passing different types of
* callback functions to
* array_walk_recursive()
* without parameters
* with less and more parameters
*/
echo "Testing array_walk_recursive() :
callback function variation.";
$input = array(array('Apple', 'Banana'),
'Mango',
array('Orange'));
echo "<br><br><br>callback function with both parameters:<br><br>";
function callback_two_parameter($value, $key)
{
// dump the arguments to check
// that they are passed
// with proper type
var_dump($key);
// key
var_dump($value);
// value
echo "<br>";
// new line to separate the
// output between each element
}
var_dump( array_walk_recursive($input,
'callback_two_parameter'));
echo "<br><br><br>callback function
with only one parameter:<br><br>";
function callback_one_parameter($value)
{
// dump the arguments to check
// that they are passed
// with proper type
var_dump($value);
// value
echo "<br>";
// new line to separate the
// output between each element
}
var_dump( array_walk_recursive($input,
'callback_one_parameter'));
echo "<br><br><br>callback function
without parameters:<br><br>";
function callback_no_parameter()
{
echo "callback3() called:<br>";
}
var_dump( array_walk_recursive($input,
'callback_no_parameter'));
echo "<br><br><br>passing one more parameter to
function with two parameters:<br><br>";
var_dump( array_walk_recursive($input,
'callback_two_parameter', 10));
?>