在symfony中将php数组转换为json格式[关闭]

I have this Json(see below) and I am trying actually to find a way to generate one like this using a php array. My question is how can I generate a json like this from a php array. in another way, I still don't know how to build that php array so that I can convert it to this a json like the one below. I am using symfony2 to render this a json like this one

var presentation = [{
                    "image": "images/cover.jpg",
                    "sentence": "This is a sentence",
                    "audio": "hello.mp3",
                    "sentence_info": [
                        {"start": 0, "end": 0.5 },
                        { "start": 0.5, "end": 1.2 }
                    ]
                },

                {
                    "image": "images/cat.jpg",
                    "sentence": "This is another sentence",
                    "audio": "bey.mp3",
                    "sentence_info": [
                        { "start": 0, "end": 0.2 },
                        { "start": 0.2, "end": 0.8 },
                        { "start": 0.8, "end": 1.2 },
                        { "start": 1.2, "end": 1.5 },
                        { "start": 1.5, "end": 2 }
                    ]
                },

                {
                    "image": "images/dog.jpg",
                    "sentence": "This is a third sentence",
                    "audio": "good.mp3",
                    "sentence_info": [
                        { "start": 0, "end": 0.5 },
                        { "start": 0.5, "end": 1.2 }
                    ]
                }
];

This is just simple array assignment in PHP. Like this:

public function whatEver()
{
    $presentation = array(
        array(
            'image' => 'images/cover.jpg',
            'sentence' => 'This is a sentence',
            'audio' => 'hello.mp3',
            'sentence_info' => array(
                array('start' => 0, 'end' => 0.5),
                array('start' => 0.5, 'end' => 1.2),
            ),
        ),
        array(
            'image' => 'images/cat.jpg',
            'sentence' => 'This is another sentence',
            'audio' => 'bey.mp3',
            'sentence_info' => array(
                array('start' => 0, 'end' => 0.2),
                array('start' => 0.2, 'end' => 0.8),
                array('start' => 0.8, 'end' => 1.2),
                array('start' => 1.2, 'end' => 1.5),
                array('start' => 1.5, 'end' => 2),
            ),
        ),
        array(
            'image' => 'images/dog.jpg',
            'sentence' => 'This is a third sentence',
            'audio' => 'good.mp3',
            'sentence_info' => array(
                array('start' => 0, 'end' => 0.5),
                array('start' => 0.5, 'end' => 1.2),
            ),
        ),
    );

    $presentation =  json_encode($presentation, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES);

    $response = new Response($presentation);
    $response->headers->set('Content-Type', 'application/json');

    return $response;
}

You would use json_encode on an array you've built up.

A simple look at the supplied json would should you that it is an array [] with various objects {} inside.

You'd be looping through data from wherever you get it from (most likely a database?) and then adding it to the array like this:

$data = array();
foreach ($data_from_wherever as $item) {
    $i = array(
        'image' => '',
        'sentence' => '',
        'audio' => '',
        'sentence_info' => array(
            array(
                'start' => '',
                'finish' => ''
            ),
            array(
                'start' => '',
                'finish' => ''
            ),
        // ......etcetc
        ),
    );

    array_push($data, $i);
}

Giving you an array that you'd json_encode() to acheive your desired output.

$presentation = json_encode($data);

And if you don't know how to get said data yet, you can simply create the $data array like below and then encode it.

$data = array(
    array(
        'image' => 'images/cover.jpg',
        'sentence' => 'This is a sentence',
        'audio' => 'hello.mp3',
        'sentence_info' => array(
            array('start' => 0, 'end' => 0.5),
            array('start' => 0.5, 'end' => 1.2),
        ),
    ),
    array(
        'image' => 'images/cat.jpg',
        'sentence' => 'This is another sentence',
        'audio' => 'bey.mp3',
        'sentence_info' => array(
            array('start' => 0, 'end' => 0.2),
            array('start' => 0.2, 'end' => 0.8),
            array('start' => 0.8, 'end' => 1.2),
            array('start' => 1.2, 'end' => 1.5),
            array('start' => 1.5, 'end' => 2),
        ),
    ),
    array(
        'image' => 'images/dog.jpg',
        'sentence' => 'This is a third sentence',
        'audio' => 'good.mp3',
        'sentence_info' => array(
            array('start' => 0, 'end' => 0.5),
            array('start' => 0.5, 'end' => 1.2),
        ),
    ),
);