How do I encode a PHP array to a JSON array, not object?

Question

I am trying to json_encode an array which is returned from a Zend_DB query.

var_dump gives: (Manually adding 0 member does not change the picture.)

array(3) {
  [1]=>
  array(3) {
    ["comment_id"]=>
    string(1) "1"
    ["erasable"]=>
    string(1) "1"
    ["comment"]=>
    string(6) "test 1"
  }
  [2]=>
  array(3) {
    ["comment_id"]=>
    string(1) "2"
    ["erasable"]=>
    string(1) "1"
    ["comment"]=>
    string(6) "test 1"
  }
  [3]=>
  array(3) {
    ["comment_id"]=>
    string(1) "3"
    ["erasable"]=>
    string(1) "1"
    ["comment"]=>
    string(6) "jhghjg"
  }
}

The encoded string looks like:

{"1":{"comment_id":"1","erasable":"1","comment":"test 1"},
 "2":{"comment_id":"2","erasable":"1","comment":"test 1"},
 "3":{"comment_id":"3","erasable":"1","comment":"jhghjg"}}

What I need is:

[{"comment_id":"1","erasable":"1","comment":"test 1"},
{"comment_id":"2","erasable":"1","comment":"test 1"},
{"comment_id":"3","erasable":"1","comment":"jhghjg"}]

Which is what the php.ini/json_encode documentation says it should look like.

Answer 1

How are you setting up your initial array?

If you set it up like:

array(
 "1" => array(...),
 "2" => array(...),
);

then you don't have an array with numeric indexes but strings, and that's converted to an object in JS world. This can happen also if you don't set a strict order (i.e. starting at 0 instead of 1).

This is a shot in the dark, however, because I can't see your original code: try setting your array without using keys at all in the first place:

array(
 array(...),
 array(...),
);

Answer 2

Added information that expands on Seb's answer.

php > print json_encode( array( 'a', 'b', 'c' ) ) ;
["a","b","c"]
php > print json_encode( array( 0 => 'a',  1 => 'b', 2 => 'c' ) ) ;
["a","b","c"]
php > print json_encode( array( 1 => 'a',  2 => 'b', 3 => 'c' ) ) ;
{"1":"a","2":"b","3":"c"}
php > 

Note: its formatting it this way with good cause:

If you were to send

{"1":"a","2":"b","3":"c"}

as

["a","b","c"]

When you did $data[1] in Php you would get back "a", but on the JavaScript side, you would get back "b" .