How to make array_walk_recursive visit every node? - php

Question

I have a recursive $data structure that I need to modify. Each node considered an $item should get a property with the value of $value added. Things that I tried (and how they failed) are:
array_walk_recursive: Visits only leaf nodes.
Stack/queue: I failed to modify the original structure but only altered the copies on the stack/queue.
Loops: Without the stack/queue approach I would need to know the nesting level and write an awful lot of nested loops.
array_map: I failed to write a proper recursive callback given that the value of $value is not static but the result of previous code. So it must somehow get "into" the callback. Since use is only available to anonymous functions I did not manage to write a recursive one.
Loop and recursive function: This answer to a similar question failed for the same reason as the array_map approach.
My situation in code looks similar to this example:
<?php
$value = 'example';
$data = array(
'foo' => 'bar'
'items' => array(
array(
'foo' => 'bar',
'items' => array(
array('foo' => 'bar')
)
)
)
);
// do this recursively to every member of an 'items' property:
$item['baz'] = $value;
Can you think of a different approach or help me straighten out one of those that I failed at so far?
Update
Some code that I tried that did not work:
// Parse error: syntax error, unexpected 'use' (T_USE), expecting '{'
function do (&$item) use ($value) {
$item['baz'] = $value;
foreach ($item['items'] as $next) {
do($next);
}
}
// Undefined variable: value
function do (&$item) {
$item['baz'] = $value;
foreach ($item['items'] as $next) {
do($next);
}
}
foreach ($data['items'] as $item) {
do($item);
}
Works for now (I would prefer not having to pass the $value parameter, though):
function do (&$item, $value) {
$item['baz'] = $value;
foreach ($item['items'] as &$next) {
do($next, $value);
}
}
foreach ($data['items'] as &$item) {
do($item, $value);
}

Answer 1

Check this code for get each key and value:
<?php
error_reporting(0);
$value = 'example';
$data = array(
'foo' => 'bar',
'items' => array( array( 'foo' => 'bar','items' => array(array('foo' => 'bar') ) ) )
);
$iterator = new RecursiveIteratorIterator(new RecursiveArrayIterator($data));
foreach ($iterator as $k => $v) {
echo $k.'=>'.$v;
echo '</br>';
}
?>
Formatting was necessary but did not suffice for the minimum edit length. So I added this otherwise useless text.

Answer 2

The following recursive function works for me. Note that it requires to pass parameters by reference also inside the foreach loop:
$value = 'example';
function do (&$item, $value) {
$item['baz'] = $value;
foreach ($item['items'] as &$next) {
do($next, $value);
}
}
foreach ($data['items'] as &$item) {
do($item, $value);
}

Answer 3

I use this method:
<?php
/**
* #param array $arr
* #param callable $callback
* #param array $options
*
*
* Example:
* (this will add the link property to every node in the array recursively)
*
*
* $linkFmt = "/mylink/{type}/{slug}";
* ArrayTool::updateNodeRecursive($ret, function (array &$row) use ($linkFmt) {
* $row['link'] = str_replace([
* "{type}",
* "{slug}",
* ], [
* $row['type'],
* $row['slug'],
* ], $linkFmt);
* });
*
*
*
*
*/
public static function updateNodeRecursive(array &$arr, callable $callback, array $options = [])
{
$childrenKey = $options['childrenKey'] ?? "children";
foreach ($arr as $k => $v) {
call_user_func_array($callback, [&$v]);
if (array_key_exists($childrenKey, $v) && $v[$childrenKey]) {
$children = $v[$childrenKey];
self::updateNodeRecursive($children, $callback, $options);
$v[$childrenKey] = $children;
}
$arr[$k] = $v;
}
}