json_encode() on a multidimensional array - with string keys

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.

This is your object:

$parent=new StdClass();$parent->ID=101;$parent->ParentID=0;$parent->Name='Root One';$child1=new StdClass();$child1->ID=1011;$child1->ParentID=$parent->ID;$child1->Name='Child One';$parent->Children[]=$child1;$child1_1=new StdClass();$child1_1->ID=10111;$child1_1->ParentID=$child1->ID;$child1_1->Name='Child One One';$child1->Children[]=$child1_1;    

This is your JSON convert function:

echo json_encode($parent,JSON_PRETTY_PRINT);

and this is your object coded into JSON format:

{    "ID": 101,    "ParentID": 0,    "Name": "Root One",    "Children": [        {            "ID": 1011,            "ParentID": 101,            "Name": "Child One",            "Children": [                {                    "ID": 10111,                    "ParentID": 1011,                    "Name": "Child One One"                }            ]        }    ]}

The answer came later because I started learning PHP later. Anyway, some day, someone might find it useful.

I have now got a working solution which is fast and works well.

1. Firstly, as written in SO link from the question;

   In JSON, arrays only have numeric keys, whereas objects have string properties. The inclusion of a array key forces the entire outer structure to be an object by necessity.

   In JSON; Curly braces hold objects ({}), Square brackets hold arrays ([]).

2. So using a string as a key will result in the json_encode function returning objects, whereas reseting the keys will ensure it creates arrays.

3. Therefore, just before I return my JSON encoded string, I run a function to reset all the array keys. The code I found on this SO thread (Reset array keys in multidimensional array) was particularly useful!