<?php
$arr = [
[
1 => [11, 110],
2 => [22, 220],
3 => [33, 330],
],
[
4 => [44, 440],
5 => [55, 550],
6 => [66, 660],
],
[
7 => [77, 770],
8 => [88, 880],
9 => [99, 990]
],
];
multi_array_visit($arr, function ($element) {
echo $element . ',';
});
function multi_array_visit($arr, $func)
{
foreach ($arr as $sub) {
if (is_array($sub)) {
//元素为数组时，继续遍历
multi_array_visit($sub, $func);
} else {
//元素不为数组时，说明到达普通元素，可以访问元素了
$func($sub);
}
}
}