Javascript 格式化flot图形数组的json数据

我使用以下php代码将温度传感器数据从MySQL数据库拉入php文件：

<?php
$hostname = 'xxxxx';
$username = 'xxxxx';
$password = 'xxxxx';
$dbname="measurements";
$usertable="temperature";

try {
$dbh = new PDO("mysql:host=$hostname;dbname=measurements", 
                           $username, $password);
/*** The SQL SELECT statement ***/
$sth = $dbh->prepare("
   SELECT
   ROUND(AVG(`temperature`),1) AS temperature,
   TIMESTAMP(LEFT(`dtg`,16)) AS dtg
   FROM `temperature`
   GROUP BY LEFT(`dtg`,16)
   ORDER BY `dtg` DESC
   LIMIT 0,800
");
$sth->execute();

/* Fetch all of the remaining rows in the result set */
$result = $sth->fetchAll(PDO::FETCH_ASSOC);
/*** close the database connection ***/
$dbh = null;

}
catch(PDOException $e)
{
    echo $e->getMessage();
}

function make_pair($date, $amount) {
return array($date, $amount);
}
$json_data = json_encode($result, JSON_NUMERIC_CHECK); 
?>

flot图形网格显示在php页面的my占位符中，但不显示任何数据

如果我使用以下格式将数据硬编码到变量dataset1中，则会出现一个图形

[1300]、[2600]、[3550]、[4400]、[5300]

我相信问题可能是由于我在php部分中格式化了json数据，因此需要对其进行格式化以进行flot图形绘制

---

我很抱歉，因为我不熟悉flot graphs，在我发布这个问题（我在这里的第一个问题）之前，在stackoverflow中尝试过许多类似的解决方案，但没有成功。任何帮助都将不胜感激

Flot希望您的数据集的格式与您传递的数据集的格式不同。我通过循环您当前的数据集（您的最后一个示例）使其以正确的格式运行

var数据集1=[{“温度”：“19.6”，“dtg”：“2016-07-28 12:53:00”}，{“温度”：“19.5”，“dtg”：“2016-07-28 12:52:00”}，{“温度”：“19.5”，“dtg”：“2016-07-28 12:51:00”}，{“温度”：“19.6”，“dtg”：“2016-07-28 12:50:00”}，{“温度”：“19.6”，“dtg”：“2016-07-28 12:49:00”}，{“温度”：“19.6”，“dtg”：，“dtg:”2016-07-28 12:47:00“，”温度“：”19.6“，”dtg:”2016-07-28 12:46:00“，”温度“：”19.6“，”dtg:”2016-07-28 12:45:00“，”温度“：”19.6“，”dtg:”2016-07-28 12:44:00“，”温度“，”19.7“，”dtg:”2016-07-28 12:43:00“，”温度“，”19.7“，”dtg:”2016-07-28:42:00“，”温度“，”19.7“，”dtg:”，”温度“，”：“19.7”，“dtg:“2016-07-28 12:40:00”{“温度”：“19.7”，“dtg:“2016-07-28 12:39:00”}，“温度”：“19.7”，“dtg:“2016-07-28 12:38:00”}，{“温度”：“19.8”，“dtg:“2016-07-28 12:37:00”}，“温度”：“19.8”，“dtg:“2016-07-28 12:36:00”{“温度”：“19.8”，“dtg:”2016-07-28:12:36:00”{“温度”：“19.8”，“dtg:”{“温度”：“19.8”、“dtg”：“2016-07-28 12:33:00”}、{“温度”：“19.8”、“dtg”：“2016-07-28 12:32:00”}、{“温度”：“19.8”、“dtg”：“2016-07-28 12:31:00”}、{“温度”：“19.8”、“dtg”：“2016-07-28 12:30:00”}、{“温度”：“19.9”、“dtg”：“2016-07-28 12:29:00”}、{“温度”：“19.9”、“dtg”：“2016-07-28:12:29:00”{2016-07-28 12:27:00，{“温度”：“19.9”，“dtg”：“2016-07-28 12:26:00”}，{“温度”：“19.9”，“dtg”：“2016-07-28 12:25:00”}，{“温度”：“19.9”，“dtg”：“2016-07-28 12:24:00”}，{“温度”：“20.0”，“dtg”：“2016-07-28 12:23:00”}，{“温度”：“20.0”，“dtg”：“2016-07-28 12:22:22:00”}，{“温度”：“20.1”，“dtg”：“，”dtg“：”2016-07-28 12:20:00“，”温度“：”20.1“，”dtg“：”2016-07-28 12:19:00“，”温度“：”20.0“，”dtg“：”2016-07-28 12:18:00“，”温度“：”20.0“，”dtg“：”2016-07-28 12:17:00“，”温度“，”20.0“，”dtg“：”2016-07-28 12:16:00“，”温度“，”20.0“，”dtg“，”2016-07-28:15:00“，”温度“，”20:00“，”dtg“，”{“温度”：“20.0”、“dtg”：“2016-07-28 12:13:00”}、{“温度”：“20.0”、“dtg”：“2016-07-28 12:12:00”}、{“温度”：“20.0”、“dtg”：“2016-07-28 12:11:00”}、{“温度”：“19.9”、“dtg”：“2016-07-28 12:10:00”}、{“温度”：“20.0”、“dtg”：“2016-07-28 12:09:00”}、{“温度”：“20.0”、“dtg”：“2016-07-28:12:00”{“温度”：“20.0”、“dtg”：2016-07-28 12:07:00，{“温度”：“20.0”，“dtg”：“2016-07-28 12:06:00”}，{“温度”：“19.9”，“dtg”：“2016-07-28 12:05:00”}，{“温度”：“19.9”，“dtg”：“2016-07-28 12:04:00”}，{“温度”：“19.9”，“dtg”：“2016-07-28 12:03:00”}，{“温度”：“19.9”，“dtg”：“2016-07-28 12:02:00”}，{“温度”：“19.9”，“dtg”：，“dtg”：“2016-07-28 12:00:00”}，{“温度”：“19.9”，“dtg”：“2016-07-28 11:59:00”}，{“温度”：“19.9”，“dtg”：“2016-07-28 11:58:00”}，{“温度”：“19.8”，“dtg”：“2016-07-28 11:57:00”}，{“温度”：“19.8”，“dtg”：“2016-07-28 11:56:00”}，{“温度”：“19.8”，“dtg”：“2016-07-28:55:00”}，{{“温度”：“19.8”、“dtg”：“2016-07-28 11:53:00”}、{“温度”：“19.7”、“dtg”：“2016-07-28 11:52:00”}、{“温度”：“19.7”、“dtg”：“2016-07-28 11:51:00”}、{“温度”：“19.7”、“dtg”：“2016-07-28 11:50:00”}、{“温度”：“19.7”、“dtg”：“2016-07-28 11:49:00”}、{“温度”：“19.7”、“dtg”：“2016-07-28 11:48:00”{2016-07-28 11:47:00，{“温度”：“19.6”，“dtg”：“2016-07-28 11:46:00”}，{“温度”：“19.7”，“dtg”：“2016-07-28 11:45:00”}，{“温度”：“19.6”，“dtg”：“2016-07-28 11:44:00”}，{“温度”：“19.6”，“dtg”：“2016-07-28 11:43:00”}，{“温度”：“19.6”，“dtg”：“2016-07-28 11:42:00”}，{“温度”：“19.6”，“dtg”：“2016-07-28:41:00”{，“dtg:”2016-07-28 11:40:00“，”温度“：”19.6“，”dtg:”2016-07-28 11:39:00“，”温度“：”19.6“，”dtg:”2016-07-28 11:38:00“，”温度“：”19.6“，”dtg:”2016-07-28 11:37:00“，”温度“，”19.6“，”dtg:”2016-07-28 11:36:00“，”温度“，”19.6“，”dtg:”2016-07-28:35:00“，”温度“，”19.6“，”dtg:”{“温度”：“19.5”、“dtg”：“2016-07-28 11:33:00”}、{“温度”：“19.5”、“dtg”：“2016-07-28 11:32:00”}、{“温度”：“19.5”、“dtg”：“2016-07-28 11:31:00”}、{“温度”：“19.5”、“dtg”：“2016-07-28 11:30:00”}、{“温度”：“19.5”、“dtg”：“2016-07-28 11:29:00”}、{“温度”：“19.5”、“dtg”：“2016-07-28:11:29:00”{2016-07-28 11:27:00，{“温度”：“19.5”，“dtg”：“2016-07-28 11:26:00”}，{“温度”：“19.5”，“dtg”：“2016-07-28 11:25:00”}，{“温度”：“19.5”，“dtg”：“2016-07-28 11:24:00”}，{“温度”：“19.4”，“dtg”：“2016-07-28 11:23:00”}，{“温度”：“19.4”，“dtg”：“2016-07-28 11:22:22:00”}，{“温度”：“19.4”，“dtg”：，“dtg”：“2016-07-28 11:20:00”}，{“温度”：“19.4”，“dtg”：“2016-07-28 11:19:00”}，{“温度”：“19.4”，“dtg”：“2016-07-28 11:18:00”}，{“温度”：“19.4”，“dtg”：“2016-07-28 11:17:00”}，{“温度”：“19.4”，“dtg”：“201”
 <script type="text/javascript">
//put array into javascript variable

var dataset1 = <?php echo json_encode($result); ?>;

//plot
$(document).ready(function () {
    $.plot($("#placeholder"),  dataset1  );
});

</script>

//put array into javascript variable

var dataset1 = [{"temperature":"19.6","dtg":"2016-07-28 12:53:00"},{"temperature":"19.5","dtg":"2016-07-28 12:52:00"},{"temperature":"19.5","dtg":"2016-07-28 12:51:00"},{"temperature":"19.6","dtg":"2016-07-28 12:50:00"},{"temperature":"19.6","dtg":"2016-07-28 12:49:00"},{"temperature":"19.6","dtg":"2016-07-28 12:48:00"},{"temperature":"19.6","dtg":"2016-07-28 12:47:00"},{"temperature":"19.6","dtg":"2016-07-28 12:46:00"},{"temperature":"19.6","dtg":"2016-07-28 12:45:00"},{"temperature":"19.6","dtg":"2016-07-28 12:44:00"},{"temperature":"19.7","dtg":"2016-07-28 12:43:00"},{"temperature":"19.7","dtg":"2016-07-28 12:42:00"},{"temperature":"19.7","dtg":"2016-07-28 12:41:00"},{"temperature":"19.7","dtg":"2016-07-28 12:40:00"},{"temperature":"19.7","dtg":"2016-07-28 12:39:00"},{"temperature":"19.7","dtg":"2016-07-28 12:38:00"},{"temperature":"19.8","dtg":"2016-07-28 12:37:00"},{"temperature":"19.8","dtg":"2016-07-28 12:36:00"},{"temperature":"19.8","dtg":"2016-07-28 12:35:00"},{"temperature":"19.8","dtg":"2016-07-28 12:34:00"},{"temperature":"19.8","dtg":"2016-07-28 12:33:00"},{"temperature":"19.8","dtg":"2016-07-28 12:32:00"},{"temperature":"19.8","dtg":"2016-07-28 12:31:00"},{"temperature":"19.8","dtg":"2016-07-28 12:30:00"},{"temperature":"19.9","dtg":"2016-07-28 12:29:00"},{"temperature":"19.9","dtg":"2016-07-28 12:28:00"},{"temperature":"19.9","dtg":"2016-07-28 12:27:00"},{"temperature":"19.9","dtg":"2016-07-28 12:26:00"},{"temperature":"19.9","dtg":"2016-07-28 12:25:00"},{"temperature":"19.9","dtg":"2016-07-28 12:24:00"},{"temperature":"20.0","dtg":"2016-07-28 12:23:00"},{"temperature":"20.0","dtg":"2016-07-28 12:22:00"},{"temperature":"20.1","dtg":"2016-07-28 12:21:00"},{"temperature":"20.1","dtg":"2016-07-28 12:20:00"},{"temperature":"20.1","dtg":"2016-07-28 12:19:00"},{"temperature":"20.0","dtg":"2016-07-28 12:18:00"},{"temperature":"20.0","dtg":"2016-07-28 12:17:00"},{"temperature":"20.0","dtg":"2016-07-28 12:16:00"},{"temperature":"20.0","dtg":"2016-07-28 12:15:00"},{"temperature":"20.0","dtg":"2016-07-28 12:14:00"},{"temperature":"20.0","dtg":"2016-07-28 12:13:00"},{"temperature":"20.0","dtg":"2016-07-28 12:12:00"},{"temperature":"20.0","dtg":"2016-07-28 12:11:00"},{"temperature":"19.9","dtg":"2016-07-28 12:10:00"},{"temperature":"20.0","dtg":"2016-07-28 12:09:00"},{"temperature":"20.0","dtg":"2016-07-28 12:08:00"},{"temperature":"20.0","dtg":"2016-07-28 12:07:00"},{"temperature":"20.0","dtg":"2016-07-28 12:06:00"},{"temperature":"19.9","dtg":"2016-07-28 12:05:00"},{"temperature":"19.9","dtg":"2016-07-28 12:04:00"},{"temperature":"19.9","dtg":"2016-07-28 12:03:00"},{"temperature":"19.9","dtg":"2016-07-28 12:02:00"},{"temperature":"19.9","dtg":"2016-07-28 12:01:00"},{"temperature":"19.9","dtg":"2016-07-28 12:00:00"},{"temperature":"19.9","dtg":"2016-07-28 11:59:00"},{"temperature":"19.9","dtg":"2016-07-28 11:58:00"},{"temperature":"19.8","dtg":"2016-07-28 11:57:00"},{"temperature":"19.8","dtg":"2016-07-28 11:56:00"},{"temperature":"19.8","dtg":"2016-07-28 11:55:00"},{"temperature":"19.8","dtg":"2016-07-28 11:54:00"},{"temperature":"19.8","dtg":"2016-07-28 11:53:00"},{"temperature":"19.7","dtg":"2016-07-28 11:52:00"},{"temperature":"19.7","dtg":"2016-07-28 11:51:00"},{"temperature":"19.7","dtg":"2016-07-28 11:50:00"},{"temperature":"19.7","dtg":"2016-07-28 11:49:00"},{"temperature":"19.7","dtg":"2016-07-28 11:48:00"},{"temperature":"19.7","dtg":"2016-07-28 11:47:00"},{"temperature":"19.6","dtg":"2016-07-28 11:46:00"},{"temperature":"19.7","dtg":"2016-07-28 11:45:00"},{"temperature":"19.6","dtg":"2016-07-28 11:44:00"},{"temperature":"19.6","dtg":"2016-07-28 11:43:00"},{"temperature":"19.6","dtg":"2016-07-28 11:42:00"},{"temperature":"19.6","dtg":"2016-07-28 11:41:00"},{"temperature":"19.6","dtg":"2016-07-28 11:40:00"},{"temperature":"19.6","dtg":"2016-07-28 11:39:00"},{"temperature":"19.6","dtg":"2016-07-28 11:38:00"},{"temperature":"19.6","dtg":"2016-07-28 11:37:00"},{"temperature":"19.6","dtg":"2016-07-28 11:36:00"},{"temperature":"19.6","dtg":"2016-07-28 11:35:00"},{"temperature":"19.6","dtg":"2016-07-28 11:34:00"},{"temperature":"19.5","dtg":"2016-07-28 11:33:00"},{"temperature":"19.5","dtg":"2016-07-28 11:32:00"},{"temperature":"19.5","dtg":"2016-07-28 11:31:00"},{"temperature":"19.5","dtg":"2016-07-28 11:30:00"},{"temperature":"19.5","dtg":"2016-07-28 11:29:00"},{"temperature":"19.5","dtg":"2016-07-28 11:28:00"},{"temperature":"19.5","dtg":"2016-07-28 11:27:00"},{"temperature":"19.5","dtg":"2016-07-28 11:26:00"},{"temperature":"19.5","dtg":"2016-07-28 11:25:00"},{"temperature":"19.5","dtg":"2016-07-28 11:24:00"},{"temperature":"19.4","dtg":"2016-07-28 11:23:00"},{"temperature":"19.4","dtg":"2016-07-28 11:22:00"},{"temperature":"19.4","dtg":"2016-07-28 11:21:00"},{"temperature":"19.4","dtg":"2016-07-28 11:20:00"},{"temperature":"19.4","dtg":"2016-07-28 11:19:00"},{"temperature":"19.4","dtg":"2016-07-28 11:18:00"},{"temperature":"19.4","dtg":"2016-07-28 11:17:00"},{"temperature":"19.4","dtg":"2016-07-28 11:16:00"},{"temperature":"19.4","dtg":"2016-07-28 11:15:00"},{"temperature":"19.4","dtg":"2016-07-28 11:14:00"},{"temperature":"19.3","dtg":"2016-07-28 11:13:00"},{"temperature":"19.3","dtg":"2016-07-28 11:12:00"},{"temperature":"19.3","dtg":"2016-07-28 11:11:00"},{"temperature":"19.3","dtg":"2016-07-28 11:10:00"},{"temperature":"19.3","dtg":"2016-07-28 11:09:00"},{"temperature":"19.3","dtg":"2016-07-28 11:08:00"},{"temperature":"19.3","dtg":"2016-07-28 11:07:00"},{"temperature":"19.3","dtg":"2016-07-28 11:06:00"},{"temperature":"19.3","dtg":"2016-07-28 11:05:00"},{"temperature":"19.3","dtg":"2016-07-28 11:04:00"},{"temperature":"19.2","dtg":"2016-07-28 11:03:00"},{"temperature":"19.2","dtg":"2016-07-28 11:02:00"},{"temperature":"19.2","dtg":"2016-07-28 11:01:00"},{"temperature":"19.2","dtg":"2016-07-28 11:00:00"},{"temperature":"19.2","dtg":"2016-07-28 10:59:00"},{"temperature":"19.2","dtg":"2016-07-28 10:58:00"},{"temperature":"19.2","dtg":"2016-07-28 10:57:00"},{"temperature":"19.2","dtg":"2016-07-28 10:56:00"},{"temperature":"19.1","dtg":"2016-07-28 10:55:00"},{"temperature":"19.1","dtg":"2016-07-28 10:54:00"},{"temperature":"19.1","dtg":"2016-07-28 10:53:00"},{"temperature":"19.1","dtg":"2016-07-28 10:52:00"},{"temperature":"19.1","dtg":"2016-07-28 10:51:00"},{"temperature":"19.1","dtg":"2016-07-28 10:50:00"},{"temperature":"19.1","dtg":"2016-07-28 10:49:00"},{"temperature":"19.1","dtg":"2016-07-28 10:48:00"},{"temperature":"19.1","dtg":"2016-07-28 10:47:00"},{"temperature":"19.1","dtg":"2016-07-28 10:46:00"},{"temperature":"19.1","dtg":"2016-07-28 10:45:00"},{"temperature":"19.0","dtg":"2016-07-28 10:44:00"},{"temperature":"19.0","dtg":"2016-07-28 10:43:00"},{"temperature":"19.0","dtg":"2016-07-28 10:42:00"},{"temperature":"19.0","dtg":"2016-07-28 10:41:00"}];

//plot
$(document).ready(function () {
    $.plot($("#placeholder"),  dataset1  );
});