将 json 对象分配给 CanvasJS 中的 javascript 变量

Question

我正在尝试将 json 对象分配给变量。我不确定如何完成此操作。

这是我的 JSON 数组：

[{
    "Date": "2020-01-24 07:35:46",
    "sensorName": "sensor 1",
    "sensorValue": 213
}, {
    "Date": "2020-01-24 07:35:46",
    "sensorName": "sensor 1",
    "sensorValue": 433
}, {
    "Date": "2020-02-10 06:03:36",
    "sensorName": "sensor 1",
    "sensorValue": 321
}, {
    "Date": "2020-02-10 06:03:36",
    "sensorName": "sensor 1",
    "sensorValue": 43
}, {
    "Date": "2020-02-12 03:30:57",
    "sensorName": "sensor 1",
    "sensorValue": 4321
}]

我想将 sensorValue 的值赋给变量 yValue。我该怎么做呢？例如：对于 "sensorValue":433，yValue = 433

<script>
var sensor1 = <?php echo json_encode($json_sensor1, JSON_NUMERIC_CHECK); ?>;
     var sensor2 = <?php echo json_encode($json_sensor2, JSON_NUMERIC_CHECK); ?>;

     var yValue1 = sensor1.sensorValue;
     var yValue2 = sensor2.sensorValue;
     var xValue = sensor1.Date;
</script>

Answer 1

CanvasJS 接受数据点作为对象数组 [{x: xValue1, y: yValue1}, {x: xValue2, y: yValue2},...]。在将 JSON 传递给图表选项之前将其解析为这种格式应该可以正常工作。

var jsonData = [{
    "Date": "2020-01-24 07:35:46",
    "sensorName": "sensor 1",
    "sensorValue": 213
}, {
    "Date": "2020-01-24 07:35:46",
    "sensorName": "sensor 1",
    "sensorValue": 433
}, {
    "Date": "2020-02-10 06:03:36",
    "sensorName": "sensor 1",
    "sensorValue": 321
}, {
    "Date": "2020-02-10 06:03:36",
    "sensorName": "sensor 1",
    "sensorValue": 43
}, {
    "Date": "2020-02-12 03:30:57",
    "sensorName": "sensor 1",
    "sensorValue": 4321
}];

var dps = [];
var chart = new CanvasJS.Chart("chartContainer", {
  title:{
    text: "Basic Column Chart"
  },
  data: [{    
    dataPoints: dps
  }]
});

for(var i = 0; i < jsonData.length; i++) {
 dps.push({ x: new Date(jsonData[i].Date), y: Number(jsonData[i].sensorValue)})
}

chart.render();

<script src="https://canvasjs.com/assets/script/canvasjs.min.js"></script>
<div id="chartContainer" style="height: 200px; width: 100%;"></div>

将 json 对象分配给 CanvasJS 中的 javascript 变量

assign json object to javascript variable in CanvasJS

javascript

php

json

canvasjs