javascript - 使用 d3.js 从 .csv 导入数据

Question

我正在尝试使用 d3.js 从 .csv 导入一些数据。我在这样做时遇到了麻烦，想知道是否有人可以伸出援手。我的 .csv 文件格式如下：

max_i,min_i,max_f,min_f
-122.1430195,-122.1430195,-122.415278,37.778643
-122.1430195,-122.1430195,-122.40815,37.785034
-122.4194155,-122.4194155,-122.4330827,37.7851673
-122.4194155,-122.4194155,-122.4330827,37.7851673
-118.4911912,-118.4911912,-118.3672828,33.9164666
-121.8374777,-121.8374777,-121.8498415,39.7241178
-115.172816,-115.172816,-115.078011,36.1586877
-82.5618186,-82.5618186,-79.2274115,37.9308282
-79.9958864,-79.9958864,-80.260396,40.1787544
-74.1243063,-74.1243063,-74.040948,40.729688
-106.609991,-106.609991,-106.015897,35.640949

我正在尝试使用以下代码加载数据：

var dataset = []
d3.csv("data.csv", function(data) {
   dataset = data.map(function(d) { return [ +d["max_i"], +d["min_i"] ]; });
});
console.log(dataset)

但是，我只是在控制台中得到一个空的 []。谁能指出我的错误？

Answer 1

将其更改为：

var dataset = []
d3.csv("data.csv", function(data) {
   dataset = data.map(function(d) { return [ +d["max_i"], +d["min_i"] ]; });
   console.log(dataset)
});

一旦您的数据返回，您需要检查回调中的数据集。