cookbook • 格式• csv

生成 CSV 输出

问题

您希望从包含键/值对数据的消息生成有效的 CSV 输出。

解决方案

CSV 节点可用于生成格式良好的 CSV 字符串。

示例

[{"id":"457d9ad6.b737b4","type":"inject","z":"64133d39.bb0394","name":"单个","topic":"","payload":"","payloadType":"date","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":90,"y":640,"wires":[["1e05fafd.887b05"]]},{"id":"1e05fafd.887b05","type":"change","z":"64133d39.bb0394","name":"生成单个有效载荷","rules":[{"t":"set","p":"payload","pt":"msg","to":"{ \"a\":$floor(100*$random()),\"b\":$floor(100*$random()),\"c\":$floor(100*$random())}","tot":"jsonata"}],"action":"","property":"","from":"","to":"","reg":false,"x":270,"y":640,"wires":[["e9546682.b39898"]]},{"id":"e9546682.b39898","type":"csv","z":"64133d39.bb0394","name":"","sep":",","hdrin":"","hdrout":false,"multi":"one","ret":"\\n","temp":"a,b,c","skip":"0","x":450,"y":640,"wires":[["f83ad3b0.78d32"]]},{"id":"f83ad3b0.78d32","type":"debug","z":"64133d39.bb0394","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","x":590,"y":640,"wires":[]},{"id":"ae242f2c.d1c8a","type":"inject","z":"64133d39.bb0394","name":"数组","topic":"","payload":"","payloadType":"date","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":90,"y":700,"wires":[["7535f521.4a88bc"]]},{"id":"7535f521.4a88bc","type":"change","z":"64133d39.bb0394","name":"生成数组有效载荷","rules":[{"t":"set","p":"payload","pt":"msg","to":"[\t    { \"a\":$floor(100*$random()),\"b\":$floor(100*$random()),\"c\":$floor(100*$random())},\t    { \"a\":$floor(100*$random()),\"b\":$floor(100*$random()),\"c\":$floor(100*$random())},\t    { \"a\":$floor(100*$random()),\"b\":$floor(100*$random()),\"c\":$floor(100*$random())},\t    { \"a\":$floor(100*$random()),\"b\":$floor(100*$random()),\"c\":$floor(100*$random())}\t]","tot":"jsonata"}],"action":"","property":"","from":"","to":"","reg":false,"x":270,"y":700,"wires":[["f4e0465f.ef0338"]]},{"id":"f4e0465f.ef0338","type":"csv","z":"64133d39.bb0394","name":"","sep":",","hdrin":"","hdrout":true,"multi":"one","ret":"\\n","temp":"a,b,c","skip":"0","x":450,"y":700,"wires":[["6eb67fdf.58626"]]},{"id":"6eb67fdf.58626","type":"debug","z":"64133d39.bb0394","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","x":590,"y":700,"wires":[]}]

讨论

在示例中，第一个流注入了一个包含三个属性的单个对象的有效载荷，这些属性包含随机生成的值。

{
    a: 10,
    b: 20,
    c: 30
}

CSV 已配置为所需的列名，并使用相应的对象属性来填充这些列。

生成的消息包含该单行数据的格式良好的 CSV 字符串 - 末尾包括换行符。

"10,20,30\n"

这适合传递给 File Out 节点，以附加到现有的 CSV 文件中。

第二个流注入了一组带有随机生成值的对象数组：

[
    { a: 80, b: 18, c: 2},
    { a: 52, b: 36, c: 10},
    { a: 91, b: 18, c: 61},
    { a: 32, b: 47, c: 65},
]

同样，CSV 节点已配置为使用的列名。它还被配置为将列名作为输出的第一行包含在内。

```javascript a,b,c 80,18,2 52,36,10 91,18,61 32,47,65

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