Drupal fetching object

Question

I am trying to fetch an object:

$field_name= 'field_test';
$json_code = $node->$field_name['und'][0]['value'];

NOT WORKING

$json_code = $node->field_test['und'][0]['value'];

WORKING

I must have variable because it's every time different field name

any solution?

Answer 1

Your PHP is incorrect for what you're trying to accomplish.

Drupal has field_get_items() for this purpose, though:

$items = field_get_items('node', $node, $field_name);
...

Answer 2

Clive is right about field_get_items() but if for some reason you absolutely want it the way you wrote it, then this will work ( notice the curly braces ) :

$json_code = $node->{$field_name}['und'][0]['value']

Though you should replace ['und'] with the constant LANGUAGE_NONE, e.g. :

$json_code = $node->{$field_name}[LANGUAGE_NONE][0]['value']