PHP函數獲取遞歸路徑密鑰與路徑

Question

給定一個數組，我想要一個數組鍵的扁平版本。每個數組鍵都需要該數組的「路徑」，並附加下劃線。

一個例子最好地解釋了這一點。

$arr = array("location"=>0,"details"=>array("width"=>0,"height"=>0,"level"=>array("three"=>0))); 

function answer($arr) {....} 

答案函數將返回此：

array("location","details_width","details_height","details_level_three"); 

UPDATE：

這裏正在進行的工作。它將接受一個數組並返回數組鍵，但沒有深度：

function recursive_keys($input) 
{ 
    $output = array_keys($input); 
    foreach($input as $sub){ 
     if(is_array($sub)){ 
      $output = array_merge($output, recursive_keys($sub)); 
     } 
    } 
    return $output; 
} 

Answer 1

function recursive_keys(array $array, array $path = array()) { 
    $result = array(); 
    foreach ($array as $key => $val) { 
     $currentPath = array_merge($path, array($key)); 
     if (is_array($val)) { 
      $result = array_merge($result, recursive_keys($val, $currentPath)); 
     } else { 
      $result[] = join('_', $currentPath); 
     } 
    } 
    return $result; 
} 

演示在這裏：http://codepad.viper-7.com/WQ3UYI

Answer 2

$ritit = new RecursiveIteratorIterator(new RecursiveArrayIterator($arr)); 
$results = array(); 
foreach ($ritit as $leafValue) { 
    $path = array(); 
    foreach (range(0, $ritit->getDepth()) as $depth) { 
     $path[] = $ritit->getSubIterator($depth)->key(); 
    } 
    $results[] = join('_', $path); 
}