PHP递归题目

$arr = [
    ‘a‘ => ‘A‘,
    ‘b‘ => ‘B‘,
    ‘c‘ => [
        ‘d‘=> ‘D‘,
        ‘e‘=>[
            ‘f‘=>‘F‘,
            ‘g‘=>[‘h‘=>‘H‘]
        ]
    ]
];

//创建一个数组处理函数
function changeCase($var,$type = CASE_UPPER){
    $var = array_change_key_case($var,$type);
      foreach($var as $key => $value){
          if(is_array($value)){
              $var[$key]=changeCase($value);
          }
      }
    return $var;
}
$res = changeCase($arr);
pre($res);

function pre($var){
    echo ‘<pre>‘;
    print_r($var);
    echo ‘</pre>‘;
}

递归这个数组 把键名 全部换成大写的