来自 MYSQL PDO 的自定义格式 JSON，用于 NVD3.js

Question

我想创建自定义格式的 JSON 以与 NVD3.js 一起使用，但不确定如何使用 PDO 创建嵌套数组？

示例数据表：

+--------------+-------------------+---------------------+
| volume_name  | volume_files_used | recorded            |
+--------------+-------------------+---------------------+
| content001   |         130435938 | 2014-08-22 13:20:44 |
| content002   |          95977391 | 2014-08-22 13:20:44 |
+--------------+-------------------+---------------------+

使用PDO 和json_encode()：

//JSON OUTPUT
$stmtJSON = $pdo->prepare("SELECT volume_name, 
                           volume_files_used, 
                           recorded FROM collection;");
$stmtJSON->execute();
$json = json_encode($stmtJSON->fetchAll(PDO::FETCH_ASSOC));
print_r($json);

当前JSON 输出：

[
    {
        "volume_name": "content001",
        "volume_files_used": "130435938",
        "recorded": "2014-08-22 13:20:44"
    },
    {
        "volume_name": "content002",
        "volume_files_used": "95977391",
        "recorded": "2014-08-22 13:20:44"
    }
]

我想要以下JSON 输出：

[
    {
        "key": "content001",
        "values": [
            {
                "x": "2014-08-22 13:20:44",
                "y": "130435938"
            }
        ]
    },
    {
        "key": "content002",
        "values": [
            {
                "x": "2014-08-22 13:20:44",
                "y": "95977391"
            }
        ]
    }
]

在上面的示例中只有两行，但实际上我想将每个volume_name 的所有values 提取为key：

[
    {
        "key": "content001",
        "values": [
            {
                "x": "2014-08-22 13:20:44",
                "y": "130435938"
            },
            {
                "x": "2014-08-22 14:20:44",
                "y": "130435940"
            },
            {
                "x": "2014-08-22 15:20:44",
                "y": "130435945"
            },
            {
                "x": "2014-08-22 16:20:44",
                "y": "130435965"
            }
        ]
    },
    {
        "key": "content002",
        "values": [
            {
                "x": "2014-08-22 13:20:44",
                "y": "95977391"
            },
            {
                "x": "2014-08-22 14:20:44",
                "y": "95977402"
            },
            {
                "x": "2014-08-22 15:20:44",
                "y": "95977445"
            },
            {
                "x": "2014-08-22 16:20:44",
                "y": "95977457"
            }
        ]
    }
]

---

回答更新

Charlotte Dunois更新输出：

{
    "content002": {
        "values": [
            {
                "y": "95583732",
                "x": "2014-08-27 11:05:01"
            },
            {
                "y": "95539534",
                "x": "2014-08-27 12:05:01"
            }
        ],
        "key": "content002"
    },
    "content001": {
        "values": [
            {
                "y": "130121075",
                "x": "2014-08-27 11:05:01"
            },
            {
                "y": "130131806",
                "x": "2014-08-27 12:05:01"
            }

        ],
        "key": "content001"
    }
}

---

工作答案

我设法从另一个开发人员那里获得了帮助。下面的代码是有效的，但如果你能做得更好，任何人都可以发表评论。

//JSON OUTPUT
$stmtJSON = $pdo->prepare("SELECT volume_name, 
                           volume_files_used, 
                           recorded FROM collection;");
$stmtJSON->execute();
$result = $stmtJSON->fetchAll(PDO::FETCH_ASSOC));

$temp_array = array();
foreach($result as $bf) {
    if (!isset($temp_array[$bf['volume_name']])) {
        $temp_array[$bf['volume_name']] = array();
    }
    $temp_array[$bf['volume_name']][] = array(
        "x" => $bf['recorded'], 
        "y" => $bf['volume_files_used']);
}

$final_array = array();

foreach ($temp_array as $volume_name => $values) {
    $final_array[] = array(
        'key' => $volume_name,
        'values' => $values);
}

$json = json_encode($final_array);

Answer 1

在将其编码为 json 对象之前，您必须使用此结构创建一个新数组。这样就可以完成工作（您的新格式化数组位于 $new_array 中，因此您可以对其进行 json 编码）：

$new_array = array();
foreach($pdo_response as $bf) {
            if(empty($new_array[$bf['volume_name']])) {
                    $new_array[$bf['volume_name']] = array("key" => $bf['volume_name'], "values" => array());
            }
    $new_array[$bf['volume_name']]['values'][] = array("x" => $bf['recoreded'], "y" => $bf['volume_files_used']);
}

如果您想要数字键 (0 - ....) 作为第一个维度，请使用 array_values()。