从PHP JSON数组中获取唯一值（为什么我必须使用implode？）

Okay, so I'm fairly new to PHP but it's enough like JS so I've been picking it up fairly quickly.

One issue I ran into the other day was getting the values from a JSON file.

My JSON file is 30,000 lines, but here's essentially what it looks like:

{
    "congress": {
        "Brown Sherrod": [{
            "birthday": "1952-11-09"
        }, {
            "gender": "M"
        }, {
            "type": "sen"
        }, {
            "state": "OH"
        }, {
            "party": "Democrat"
        }],
        ...

And anyway, it continues like that for another 29,000 + lines. My code to get the contents of the JSON file is this:

$data = json_decode(file_get_contents('path/to/file/convertcsv.json'), true);

It returns an array like this:

Array (
    [0] => Array (
        [birthday] => 1952-11-09
    )
    [1] => Array (
        [gender] => M
    )
    [2] => Array (
        [type] => sen
    )
    [3] => Array (
        [state] => OH
    )
    [4] => Array (
        [party] => Democrat
    )
)

My issue I ran into is that I can't get the value of, say, ['birthday'] without using implode().

This works: $state = implode($data['congress'][$nameInput][3]);, but this does not: $state = $data['congress'][$nameInput][3];

Is there a reason why? I've read the docs on implode() (join array elements with string) and from what I gather from SO and the PHP docs this is how you get the value, but why? It makes no sense to have to convert the array to a string in order to get the value. In JavaScript to get the value from an array (or even a key-value) you just use the ['key'] or the [index] of the array, and it'll give you the value.

I feel like either I'm goofing on something major (not unlikely) or PHP is just weird -- probably the former. So, to reiterate my question (because I can ramble) am I making this too complex or is PHP just weird (and if so, is there a reason)?

Try below :-

$state = $data['congress'][$nameInput][3]['state']