在谷歌折线图中的同一行上组合实线和虚线格式

google.charts.load('current', {
  callback: function () {
    new google.visualization.LineChart(document.getElementById('chart_div')).draw(
      new google.visualization.DataTable({
        "cols": [
          {"type": "string", "label": "Year"},
          {"type": "number", "label": "Sales"},
          {"type": "boolean", "role": "certainty"}
        ],
        "rows": [
          {"c": [{"v": "2014"}, {"v": 1000}, {"v": true}]},
          {"c": [{"v": "2015"}, {"v": 1070}, {"v": true}]},
          {"c": [{"v": "2016"}, {"v": 1200}, {"v": true}]},
          {"c": [{"v": "2017"}, {"v": 1070}, {"v": false}]},  // <-- dashed
          {"c": [{"v": "2018"}, {"v": 1200}, {"v": false}]}   // <-- dashed
        ]
      })
    );
  },
  packages:['corechart']
});

<script src="https://www.gstatic.com/charts/loader.js"></script>
<div id="chart_div"></div>