从JSON格式的字符串转换为可下载的JSON文件

I start with an Array:

我从一个数组开始:

$arr = array(
        0 => array(
            'name' => Input::get('symptom'),
            'amount' => 5,
            'time' => '2:00 am',
            'date' => '10.26.96',
            'type' => 'symptom',
        )
$arr = arr