var a1 = lineGroup.selectAll("circle")[0]; // gives array of circles
//Here is my code which is not working:
var a1 = lineGroup.selectAll("circle")[0];
function classArray() {
return lineGroup.select("circle").attr("class");
}
var a = a1.map(classArray);
以下是我得到的一系列圈子：
[<circle cx="74" cy="425.5" r="8" class="limited circleSmall preliteracy"></circle>, <circle cx="108" cy="368" r="8" class="intermediate circleSmall earlywriting"></circle>, <circle cx="142" cy="273.7" r="8" class="advanced circleSmall preliteracy"></circle>, <circle cx="346" cy="391" r="8" class="basic circleSmall writing"></circle>, <circle cx="380" cy="460" r="8" class="limited circleSmall preliteracy"></circle>, <circle cx="380" cy="172.5" r="8" class="basic circleSmall reading"></circle>, <circle cx="414" cy="151.79999999999998" r="8" class="basic circleSmall reading"></circle>, <circle cx="448" cy="105.8" r="8" class="intermediate circleSmall reading"></circle>, <circle cx="482" cy="96.59999999999998" r="8" class="intermediate circleSmall reading"></circle>, <circle cx="516" cy="80.50000000000001" r="8" class="high circleSmall reading"></circle>]
我的疑问是，我如何检查我的班级名称是精读，阅读，高级，中级，写作，早期写作（即类的价值）？ 我怎么能在不同的数组中获得类名？