如何在php中读取多级json的值？

Question

I have the following code to read a Json and store some values into an array:

<?php
$json = '[{
        "provider_id":1,
        "nro_chart":1,
        "control": {
            "color": "blue",
            "total_value": 21.5,
            "car_id": 421118
        }
    },
    {
        "control": {
            "color": "green",
            "total_value": 25,
            "car_id": 421119
        }
    },
    {
        "control": {
            "color": "red",
            "total_value": 18,
            "car_id": 421519
        }
    }
]';

$j = json_decode($data);
$result = [];
foreach ($j as $item) {
    array_push($result,[
        'total_value' => $item->control->total_value,
        'car_id' => $item->control->car_id
    ]);
}

Now I need to get the two values that are outside of "control" like "provider_id" and "nro_chart" inside a variable.

Answer 1

The JSON contains an array of one element, so to access provider_id and nro_chart, get the first element and directly access the properties:

$j = json_decode($json);
var_dump($j[0]->provider_id); // /Applications/MAMP/htdocs/trello/up.php:28:int 1
var_dump($j[0]->nro_chart); // /Applications/MAMP/htdocs/trello/up.php:28:int 1

Demo

Or, within that same foreach loop:

foreach ($j as $item) {
    array_push($result,[
        'total_value' => $item->control->total_value,
        'car_id' => $item->control->car_id
    ]);
    if (isset($item->provider_id)) {
        var_dump($item->provider_id);
    }
    if (isset($item->nro_chart)) {
        var_dump($item->nro_chart);
    }
}

Be sure to check if the property is set for that element with isset() first.