PHP函數返回NULL，而不是字符串

Question

我有存儲在它的所有類別的數組：

$allCatArray = array(
         ['departments/outdoor/123123/'] => stdClass Object 
          (
           [i] => 1 
           [id] => 'departments/outdoor/123123/' 
           [pid] => 'departments/outdoor/' 
           [name] => 'Child Category Name' 
         ) 
         ['departments/outdoor/'] => stdClass Object 
          (
          [i] => 1 
          [id] => 'departments/outdoor/' 
          [pid] => '0' 
          [name] => 'Main Category Name' 
         ) 

我需要檢測的最高類別中的層次結構，當我在較低層次類別ID。所以我有這樣的功能：

function findMainCategoryFromAllCatArray($initial_category, $allCatArray) { 
    $pid = trim($allCatArray[$initial_category]->pid); 
    if($pid != "0") { 
    findMainCategoryFromAllCatArray($pid, $allCatArray); 
    } 
    elseif($pid == "0") { 
    var_dump($allCatArray[$initial_category]->name); // this var dump returns normal value 
    return $allCatArray[$initial_category]->name; 
    } 
    else { 
    return false; 
    } 
} 

嘗試使用此功能時，我越來越麻煩：

$category_name = findMainCategoryFromAllCatArray('departments/outdoor/123123/', $allCatArray); 
var_dump($category_name); // returns NULL instead of "Main Category Name" 

任何想法？

Answer 1

替換此：

if($pid != "0") { 
    findMainCategoryFromAllCatArray($pid, $allCatArray); 
} 

與

if($pid != "0") { 
    return findMainCategoryFromAllCatArray($pid, $allCatArray); 
} 

，因爲當上入手，函數返回什麼$pid != "0" - >您NULL值