Polymer 如何在google图表linr图形中显示多行

我有如下代码：

<google-chart type='line' options='{"title": "Sales Statistics, Billions", "vAxis": {"minValue" : 0, "maxValue": 40}, "curveType": "function"}' rows='[["Monday", 31], ["Tuesday", 28], ["Wednesday", 31], ["thursday", 22], ["friday", 11]]' cols='[{"label":"Weeks", "type":"string"}, {"label":"Days", "type":"number"}]'></google-chart>

代码运行良好。但是，我不知道如何显示多行数据。 这意味着我的输出是

我想要这样：

<google-chart type='line' options='{"title": "Sales Statistics, Billions", "vAxis": {"minValue" : 0, "maxValue": 40}, "curveType": "function"}' rows='[["Monday", 31], ["Tuesday", 28], ["Wednesday", 31], ["thursday", 22], ["friday", 11]]' cols='[{"label":"Weeks", "type":"string"}, {"label":"Days", "type":"number"}]'></google-chart>

---

谢谢。

我找到了解决问题的办法。将另一个元素添加到

cols

数组

cols='[{"label":"Weeks", "type":"string"}, {"label":"Days", "type":"number"}, {"label":"Days", "type":"number"}]'

并将另一个元素添加到行数组中，作为图形中另一条线的坐标，如下所示

rows='[["Monday", 31, 11], ["Tuesday", 28, 22], ["Wednesday", 31, 33], ["thursday", 22, 44], ["friday", 11, 44]]'

谢谢