Q:

How can i access all values within a nested array in php by defining a specific key? 

I am creating an routing application and get the result as an json array.  After transforming it into an php array i get the whole distance and whole duration correctly.  Now i need for every value in the key "legs" the distances and durations too but all i did to get the data doesnt work. 
The json output of the array looks like this: 
array (
  'routes' => 
  array (
    0 => 
    array (
      'legs' => 
      array (
        0 => 
        array (
          'summary' => '',
          'weight' => 3741.9,
          'duration' => 2912.3, // This value is what i want access
          'steps' => 
          array (
          ),
          'distance' => 21603.1, // This value is what i want access
        ),
        1 => 
        array (
          'summary' => '',
          'weight' => 3642.1,
          'duration' => 2777.4, // This value is what i want access
          'steps' => 
          array (
          ),
          'distance' => 21611.8, // This value is what i want access
        ),
      ),
      'weight_name' => 'routability',
      'weight' => 7384,
      'duration' => 5689.700000000001, // This value i can acesss
      'distance' => 43214.899999999994, // This value i can acesss too
    ),
  ),
  'waypoints' => 
  array (
    0 => 
    array (
      'hint' => '',
      'distance' => 16.78277948979663, // This value is what i want access
      'name' => 'Weg',
      'location' => 
      array (
        0 => 11.4623,
        1 => 50.7126,
      ),
    ),
    1 => 
    array (
      'hint' => '',
      'distance' => 16.62835508134535,
      'name' => 'Weg',
      'location' => 
      array (
        0 => 12.6069,
        1 => 51.5398,
      ),
    ),
    2 => 
    array (
      'hint' => '',
      'distance' => 16.78277948979663,
      'name' => 'Weg',
      'location' => 
      array (
        0 => 12.343,
        1 => 51.576,
      ),
    ),
  ),
  'code' => 'Ok',
)

The whole distance (43214.8) and whole duration (5689.7) i get by the following code:
foreach($res2['routes'] as $item) 
{
    $distances = array_push_assoc($distances, $item['distance'], $item['duration']);
}

In order to get the distances and durations i did the following:
foreach($res2['routes']['legs'] as $item) 
{
    $durations = array_push_assoc($durations , "DUR", $item['duration']);
}

How can i get the distances and durations from "legs"?  Why doenst work $res2['routes']['legs']? 
Thank you! 

A:

Do notice the the "legs" array exists in index 0 of the "routes" array so looping on it will require using $res2['routes'][0]['legs']. 
Morever, notice that using array_push_assoc in loop with the same hard-coded key (as "DUR" in your example) will override the key each time so your data gets lost - you better change it to:
foreach($res2['routes'][0]['legs'] as $item) {
    $durations[] = $item['duration'];
}

