Question

I have a PHP data structure I want to JSON encode. It can contain a number of empty arrays, some of which need to be encoded as arrays and some of which need to be encoded as objects.

For instance, lets say I have this data structure:

$foo = array(
  "bar1" => array(), // Should be encoded as an object
  "bar2" => array() // Should be encoded as an array
);

I would like to encode this into:

{
  "bar1": {},
  "bar2": []
}   

But if I use json_encode($foo, JSON_FORCE_OBJECT) I will get objects as:

{
  "bar1": {},
  "bar2": {}
}

And if I use json_encode($foo) I will get arrays as:

{
  "bar1": [],
  "bar2": []
}

Is there any way to encode the data (or define the arrays) so I get mixed arrays and objects?

Answer 1

Create bar1 as a new stdClass() object. That will be the only way for json_encode() to distinguish it. It can be done by calling new stdClass(), or casting it with (object)array()

$foo = array(
  "bar1" => new stdClass(), // Should be encoded as an object
  "bar2" => array() // Should be encoded as an array
);

echo json_encode($foo);
// {"bar1":{}, "bar2":[]}

OR by typecasting:

$foo = array(
  "bar1" => (object)array(), // Should be encoded as an object
  "bar2" => array() // Should be encoded as an array
);

echo json_encode($foo);
// {"bar1":{}, "bar2":[]}