PHP array_walk_recursive：两种方法，结果不同

Question

Given the following setup: 给定以下设置：

    $storer = array();
    $arr = array(1, 2, 3);

I'm curious why this does not write to $storer ... 我很好奇为什么这不写到$storer ...

array_walk_recursive($arr, function($val, $key) {
    global $storer;
    $storer[] = 'foo';
});
print_r($storer); //no change - empty

..but this does: ..但是这样做：

array_walk_recursive($arr, function($val, $key) use (&$storer) {
    $storer[] = 'foo';
});
print_r($storer); //three items, all 'foo'

Can anyone enlighten me? 谁能启发我？ In a user function I would expect global to provide read/write access. 在用户函数中，我希望global变量提供读/写访问权限。

Answer 1

After pulling my hair out trying to get a flattened array with keys this works: 将我的头发拔出后，尝试使用键获取一个扁平数组，这可行：

$result = array();

array_walk_recursive($inputarray,function($v, $k) use (&$result){ $result[$k] = $v;  });

$inputarray = $result;

I hope someone finds this and it helps. 我希望有人能找到它并有所帮助。