json_encode() on a multidimensional array - with string keys

Question

I am creating an very large multidimensional array using PHP. Each object contains Name, ID, ParentID and Children. Children is an array of more objects in the same format.

It is critical I name the IDs of each object - this helps me put each object under the correct parent. (In the code below, I use 101, 102 etc.)

However, the problem I am having is when I return the array in JSON using json_encode. Each 'Children' array is being printed as an object, not an array - as shown in the JSON code below.

As I read on another SO thread here, they "are made as objects because of the inclusion of string keys" - although they are numbers, they are still strings.

{
"101": {
    "ID": "101",
    "ParentID": "0",
    "Name": "Root One"
    "Children": {
        "102": {
            "ID": "102",
            "ParentID": "101",
            "Name": "Child One"
        },
        "103": {
            "ID": "103",
            "ParentID": "101",
            "Name": "Child Two",
            "Children": {
                "104": {
                    "ID": "104",
                    "ParentID": "103",
                    "Name": "Child Child One"
                }
            }
        },

Does anyone know how to overcome this issue?

Edit: The JSON should look like this (the square brackets are important!):

[
{
    "ID": "101",
    "ParentID": "0",
    "Name": "Root One",
    "Children": [
        {
            "ID": "102",
            "ParentID": "101",
            "Name": "Child One",
            "Children": [

Answer 1

A JSON array has no explicit indexes, it's just an ordered list. The only JSON data structure that has named keys is an object. The literal should make this quite obvious:

["foo", "bar", "baz"]

This array has no named indices and there isn't any provision to add any.

PHP conflates both lists and key-value stores into one array data type. JSON doesn't.