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格式化flot图形数组的json数据

flot json php javascript
  •  3
  • Huw  · 技术社区  · 9 年前

    我使用以下php代码将温度传感器数据从MySQL数据库提取到php文件中: 

    <?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); 
?>

    然后,我使用javascript在浮标图中绘制此数据: 

     <script type="text/javascript">
//put array into javascript variable

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

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

</script>

    当我在浏览器中打开php文件并查看javscript控制台时,我可以看到数据通过ok进入并作为变量dataset1保存

    它看起来像这样: 

    //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  );
});

    在php页面的占位符中会显示一个flot图形网格,但不会显示任何数据。

    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。

    [[1, 300], [2, 600], [3, 550], [4, 400], [5, 300]];

    我认为问题可能是由于我在php部分中对json数据进行了格式化,因此需要对其进行格式化以便绘制浮图。

    我很抱歉,因为我是一个新手,在我发布这个问题(我在这里的第一个问题)之前,我在stackoverflow中尝试了许多类似的解决方案,但都没有成功。任何帮助都将不胜感激!

    1 回复  |  直到 9 年前
        1
  •  1
  •   Bill the Lizard    9 年前

    Flot希望您的数据集与您传入的数据集的格式不同。我通过循环当前的数据集(上一个示例),将其转换为正确的格式,从而实现了它。 

    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"}];

var dataset2 = [];
for (var i = 0; i < dataset1.length; i++) {
    dataset2.push( [ Date.parse(dataset1[i].dtg), 
	             parseFloat(dataset1[i].temperature) ] );
}
			
//plot
$(document).ready(function () {
    $.plot( $("#placeholder"),
            [dataset2], // wrap data series in a container
            { xaxis: { mode: "time" } }
    );
});
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<script src="http://cdnjs.cloudflare.com/ajax/libs/flot/0.7/jquery.flot.min.js"></script>
<div id="placeholder" style="width:600px; height:400px; float: left;"></div>

    之后 var dataset2 = []; ,循环将解包数据集中的每个元素,并创建一个 [date, temp] 要添加到阵列中的数据点。我必须同时分析日期和浮动,因为Flot需要的是数字数据,而不是字符串。

    这将创建一个数据系列。您可以在Flot中绘制多个数据系列,因此请注意,在调用 plot (换言之,该容器可能已经 [dataset2, dataset3, ..., datasetX] .)

    所需的最后一步是设置 { mode: "time" } 在x轴上。

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