I have some content types (nodes) that are attached to various taxonomies. For specific node types, I want to do some validation on the taxonomy. I do not want to hard-code the nodes types and their corresponding fields that reference the taxonomy. So I put them in array. However, I am unable to dereference the field names. I've tried double $$, quotes, etc, but can't get it to work. Is what I want to do possible?


$node = (object) array(
    'nid' => NULL,
    'vid' => NULL,
    'uid' => '1',
    'type' => 'price_document',
    'language' => 'und',
    'field_taxonomy_price' => array(
        'und' => array(
                'tid' => '94'

  $nodes_to_check = array("price_document" => "field_taxonomy_price",
                          "package"        => "field_taxonomy_package",

  if (array_key_exists($node->type,$nodes_to_check)) {
    $taxonomy_field = $nodes_to_check[$node->type];
    $tid = $node->field_taxonomy_price ['und'][0]['tid']; //  <- this works but, how
    //$tid = $node->"$$taxonomy_field" ['und'][0]['tid'];     <- can I deref variable?

1 Answer 1


You just need to use curly braces; there's no need for variable variables in this case:

$tid = $node->{$taxonomy_field}['und'][0]['tid'];

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