PHP json_encode issue with array 0 key

Question

I am having a problem using json_encode to generate a json encoded string from an array.

The section of the array in question looks like this

RatingDistribution (Array, 11 elements)
    0 (Array, 1 element)
        0 (String, 3 characters ) 4.5
    1 (Array, 1 element)
        1 (String, 4 characters ) 11.9
    2 (Array, 1 element)

But produces this in the string:

"RatingDistribution":[["4.5"],{"1":"11.9"},

I would expect this:

"RatingDistribution":[{"0":"4.5"},{"1":"11.9"},

All I'm doing is this:

$result = json_encode($array);

Have I done something wrong or do I need more code to ensure the 0 key is present?

Cheers Andy

Answer 1

If you want to use arrays in your json then instead of JSON_FORCE_OBJECT parameter you can simply cast array to object.

Problem:

json_encode([0 => [1,2,3]]); // Return: [[1,2,3]]
json_encode(["0" => [1,2,3]]); // Return: [[1,2,3]]
json_encode([1 => [1,2,3]]); // Return: {"1":[1,2,3]}

Not what we expect :

json_encode([0 => [1,2,3]], JSON_FORCE_OBJECT); // Return: {"0":{"0":1,"1":2,"2":3}}

Solution:

json_encode((object)[0 => [1,2,3]]); // Return: {"0":[1,2,3]}
json_encode(new \ArrayObject([0 => [1,2,3]])); // Return: {"0":[1,2,3]}

Answer 2

The result you are getting should be expected; json_encode detects that you are only using numeric keys in the array, so it translates that to an array instead of an object in JSON. Most of the time, that's exactly what you want to do.

If for some reason you don't (why?), in PHP >= 5.3 you can use the JSON_FORCE_OBJECT flag to get your desired output:

$result = json_encode($array, JSON_FORCE_OBJECT);