Question

回调函数draw似乎无法访问提供给d3.csv()的回调内的数据。在回调console.log中打印：

data：null

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>Correlation XX</title>
    <script src="d3v4.js"></script>
    <script type="text/javascript">

      function draw(data) {
        console.log("data: " + data); // <-- talking about this line
        var width = 860,
            height = 500;

        var svg = d3.select("body")
                  .append("svg")
                  .attr("width", width)
                  .attr("height", height)
                  .append("g")
                  .attr("transform", "translate(50, 50)");
      }
    </script>
  </head>
  <body>
    <script type="text/javascript">
      d3.csv("modified_data_titanic.csv", function(data) {
        data.forEach(function(d) {
          d.Age = +d.Age;
          d.Survived = +d.Survived;
        });
      }, draw);
    </script>
  </body>
</html>

csv-data：

"","PassengerId","Survived","Pclass","Name","Sex","Age","SibSp","Parch","Ticket","Fare","Cabin","Embarked","Child","Survived_new","Category"
"1",1,0,3,"Braund, Mr. Owen Harris","male",22,1,0,"A/5 21171",7.25,"","S","FALSE",0,"20-29 m"
"2",2,1,1,"Cumings, Mrs. John Bradley (Florence Briggs Thayer)","female",38,1,0,"PC 17599",71.2833,"C85","C","FALSE",0,"30-39 f"
"3",3,1,3,"Heikkinen, Miss. Laina","female",26,0,0,"STON/O2. 3101282",7.925,"","S","FALSE",0,"20-29 f"
"4",4,1,1,"Futrelle, Mrs. Jacques Heath (Lily May Peel)","female",35,1,0,"113803",53.1,"C123","S","FALSE",0,"30-39 f"
"5",5,0,3,"Allen, Mr. William Henry","male",35,0,0,"373450",8.05,"","S","FALSE",0,"30-39 m"
"6",6,0,3,"Moran, Mr. James","male",NA,0,0,"330877",8.4583,"","Q",NA,0,NA
"7",7,0,1,"McCarthy, Mr. Timothy J","male",54,0,0,"17463",51.8625,"E46","S","FALSE",0,"50-59 m"
"8",8,0,3,"Palsson, Master. Gosta Leonard","male",2,3,1,"349909",21.075,"","S","TRUE",0,"0-9 m"
"9",9,1,3,"Johnson, Mrs. Oscar W (Elisabeth Vilhelmina Berg)","female",27,0,2,"347742",11.1333,"","S","FALSE",0,"20-29 f"
"10",10,1,2,"Nasser, Mrs. Nicholas (Adele Achem)","female",14,1,0,"237736",30.0708,"","C","TRUE",0,"10-19 f"
"11",11,1,3,"Sandstrom, Miss. Marguerite Rut","female",4,1,1,"PP 9549",16.7,"G6","S","TRUE",0,"0-9 f"
"12",12,1,1,"Bonnell, Miss. Elizabeth","female",58,0,0,"113783",26.55,"C103","S","FALSE",0,"50-59 f"
"13",13,0,3,"Saundercock, Mr. William Henry","male",20,0,0,"A/5. 2151",8.05,"","S","FALSE",0,"20-29 m"

背景信息：我的实际目标是使用 Age 或 Survived 等列作为x轴的范围。

Answer 1

您的行转换功能，即d3.csv()的第二个参数，不正确。有关详细信息，请查看documentation：

如果指定了行转换函数，则为每一行调用指定的函数，传递一个表示当前行（d）的对象，即索引（{{1} }）从第一个非标题行开始为零，以及列名称数组。如果返回的值为null或未定义，则跳过该行，并且将从 dsv .parse;返回的数组中省略该行。否则，返回的值定义相应的行对象。

有两个问题：

为每一行调用该函数，而不是像调用函数那样调用整个数据。
Adrian在他的comment中指出，你需要返回行的值;否则，将跳过该行。

以下功能应该可以解决问题：

Answer 2

您的访问者（或行）功能不正确。

首先，访问者功能不需要forEach。除此之外，你必须返回每一行。总之，这些是变化：

d3.csv("modified_data_titanic.csv", function(d) {
     d.Age = +d.Age;
     d.Survived = +d.Survived;
     return d;
 }, draw);

在d3.csv（）方法的回调函数中无法访问我的数据

2 个答案: