D3.js d3JS有序标度直方图

D3.js d3JS有序标度直方图,d3.js,histogram,visualization,ordinal,D3.js,Histogram,Visualization,Ordinal,我试图得到一个有序的D3JS直方图(在本例中,是学生成绩符号(a+,a,B…F)) 以下是一个最低限度的工作示例: <!DOCTYPE html> <meta charset="utf-8"> <body> <script src="http://d3js.org/d3.v3.min.js"></script> <script> var studentSymbols = ["F", "E", "D", "C", "

我试图得到一个有序的D3JS直方图(在本例中,是学生成绩符号(a+,a,B…F))

以下是一个最低限度的工作示例:

<!DOCTYPE html>
<meta charset="utf-8">

<body>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script>
    var studentSymbols = ["F", "E", "D", "C", "C", "C", "C", "B", "B", "A", "A+"];

    var x = d3.scale.ordinal()
        .domain(["F", "E", "D", "C", "B", "A", "A+"])
        .rangeRoundBands([0, width]);

    // Generate a histogram using twenty uniformly-spaced bins.
    var myHistogram = d3.layout.histogram()
        (studentSymbols);

    console.log(myHistogram)
</script>
</body>

var studentSymbols=[“F”、“E”、“D”、“C”、“C”、“C”、“B”、“B”、“A”、“A+”];
var x=d3.scale.ordinal()
.域([“F”、“E”、“D”、“C”、“B”、“A”、“A+”]))
.rangeRoundBands([0,宽度]);
//使用20个均匀间隔的容器生成直方图。
var myHistogram=d3.layout.histogram()
(学生符号);
console.log(myHistogram)
运行上述命令时,控制台输出一个由5个数组组成的数组,其中dx和x字段等于NaN


我应该如何更正此代码?

我想我可能已经解决了。我将myHistogram的声明更改为:

    var myHistogram = d3.layout.histogram()
        (studentSymbols.map(x));