Some interesting task related to recursion and arrays in PHP

Sometimes it is difficult to find best solution for some problem quickly.
For example, if you need to walk some nested array. You don’t know how deep it could be nested and extract values from it to make it flattern you can use amazing function array_walk_recursive together with anonymous function to solve such task like it is shown in example below:

$inputArray = [9, [7, 5, [11, [3]]], 14];
array_walk_recursive($inputArray, function($value, $key) use (&$resultArray) {
    $resultArray[] = $value;

This amazing example of magic is very simple: it calls our anonymous function for each $inputArray element, storing nested element values in $resultArray. Note, usage of & in use (&$resultArray) it tells we shoud pass variable by reference.