PHPで配列の次元数を確認する方法

/**
 * 判断数组维度
 * 
 * @param array $arr
 * @return int
 */
function array_dimension($arr)
{
  $dimension = 0;
  if (is_array($arr)) {
    foreach ($arr as $item) {
      if (is_array($item)) {
        $sub_dimension = array_dimension($item);
        if ($sub_dimension > $dimension) {
          $dimension = $sub_dimension;
        }
      }
    }
    $dimension++;
  }
  return $dimension;
}
// 示例数据
$arr1 = array(1, 2, 3);
$arr2 = array(array(1, 2), array(3, 4));
$arr3 = array(array(array(1, 2), array(3, 4)), array(array(5, 6), array(7, 8)));
echo &#39;数组1的维度：&#39; . array_dimension($arr1) . &#39;<br>&#39;;
echo &#39;数组2的维度：&#39; . array_dimension($arr2) . &#39;<br>&#39;;
echo &#39;数组3的维度：&#39; . array_dimension($arr3) . &#39;<br>&#39;;

/**
 * 判断数组维度
 * 
 * @param array $arr
 * @return int
 */
function array_dimension($arr)
{
  $json_arr = json_encode($arr, JSON_UNESCAPED_UNICODE);
  $max_depth = 1;
  if (preg_match_all('/(?:^|\{|\,)\s*(\[(?R)*\]|\{(?R)*\})\s*(?:(?=\:)|$)/', $json_arr, $m)) {
    foreach ($m[1] as $val) {
      $depth = substr_count(str_replace(["[", "{", "]", "}"], "", $val), ',') + 1;
      if ($depth > $max_depth) {
        $max_depth = $depth;
      }
    }
  }
  return $max_depth;
}
// 示例数据
$arr1 = array(1, 2, 3);
$arr2 = array(array(1, 2), array(3, 4));
$arr3 = array(array(array(1, 2), array(3, 4)), array(array(5, 6), array(7, 8)));
echo &#39;数组1的维度：&#39; . array_dimension($arr1) . &#39;<br>&#39;;
echo &#39;数组2的维度：&#39; . array_dimension($arr2) . &#39;<br>&#39;;
echo &#39;数组3的维度：&#39; . array_dimension($arr3) . &#39;<br>&#39;;