PHP等效于此Javascript代码段

JavaScript:

var chartData = [];
     for (var i = 0; i< data.prices.length; i++)
      {
        chartData.push
        ({
        "date": data.prices[i][0],
        "value": data.prices[i][1],
        "volume": data.total_volumes[i][1]
        });  
      }

My attempt (PHP):

$chartData = [];
    $length = count($data->prices);

    for ($i = 0; $i < $length; $i++)     
    {
    $chartData[] = array($data->prices[$i][0],$data->prices[$i][1],$data->total_volumes[$i][1]);
    }  

I'm trying to handle data from an API server side with php and then encode the data for javascript. I'm stuck converting this javascript snippet to PHP at the "date": "value": and "volume": I don't know what the equivalent to this would be in PHP. It looks as though they are labels in javascript to the data being pushed to the array? How do I give the data being pushed to the array the same labels in PHP?

You were pretty close you can define keys and values in PHP by doing:

$chartData[] = array(
   "date"   => $data->prices[$i][0],
   "value"  => $data->prices[$i][1],
   "volume" => $data->total_volumes[$i][1]
);

Here's a "clever" way:

$chartData = array_map(function($price,$volume) {
    return array(
        "date" => $price[0],
        "value" => $price[1],
        "volume" => $volume[1]
    );
}, $data->prices, $data->total_volumes);